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1 @c -*-texinfo-*-
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2 @c This is part of the XEmacs Lisp Reference Manual.
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3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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4 @c See the file lispref.texi for copying conditions.
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5 @setfilename ../../info/processes.info
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6 @node Processes, System Interface, Databases, Top
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7 @chapter Processes
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8 @cindex child process
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9 @cindex parent process
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10 @cindex subprocess
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11 @cindex process
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12
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13 In the terminology of operating systems, a @dfn{process} is a space in
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14 which a program can execute. XEmacs runs in a process. XEmacs Lisp
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15 programs can invoke other programs in processes of their own. These are
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16 called @dfn{subprocesses} or @dfn{child processes} of the XEmacs process,
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17 which is their @dfn{parent process}.
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18
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19 A subprocess of XEmacs may be @dfn{synchronous} or @dfn{asynchronous},
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20 depending on how it is created. When you create a synchronous
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21 subprocess, the Lisp program waits for the subprocess to terminate
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22 before continuing execution. When you create an asynchronous
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23 subprocess, it can run in parallel with the Lisp program. This kind of
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24 subprocess is represented within XEmacs by a Lisp object which is also
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25 called a ``process''. Lisp programs can use this object to communicate
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26 with the subprocess or to control it. For example, you can send
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27 signals, obtain status information, receive output from the process, or
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28 send input to it.
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29
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30 @defun processp object
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31 This function returns @code{t} if @var{object} is a process,
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32 @code{nil} otherwise.
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33 @end defun
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34
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35 @menu
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36 * Subprocess Creation:: Functions that start subprocesses.
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37 * Synchronous Processes:: Details of using synchronous subprocesses.
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38 * MS-DOS Subprocesses:: On MS-DOS, you must indicate text vs binary
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39 for data sent to and from a subprocess.
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40 * Asynchronous Processes:: Starting up an asynchronous subprocess.
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41 * Deleting Processes:: Eliminating an asynchronous subprocess.
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42 * Process Information:: Accessing run-status and other attributes.
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43 * Input to Processes:: Sending input to an asynchronous subprocess.
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44 * Signals to Processes:: Stopping, continuing or interrupting
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45 an asynchronous subprocess.
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46 * Output from Processes:: Collecting output from an asynchronous subprocess.
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47 * Sentinels:: Sentinels run when process run-status changes.
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48 * Process Window Size:: Changing the logical window size of a process.
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49 * Transaction Queues:: Transaction-based communication with subprocesses.
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50 * Network:: Opening network connections.
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51 @end menu
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52
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53 @node Subprocess Creation
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54 @section Functions that Create Subprocesses
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55
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56 There are three functions that create a new subprocess in which to run
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57 a program. One of them, @code{start-process}, creates an asynchronous
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58 process and returns a process object (@pxref{Asynchronous Processes}).
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59 The other two, @code{call-process} and @code{call-process-region},
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60 create a synchronous process and do not return a process object
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61 (@pxref{Synchronous Processes}).
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62
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63 Synchronous and asynchronous processes are explained in following
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64 sections. Since the three functions are all called in a similar
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65 fashion, their common arguments are described here.
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66
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67 @cindex execute program
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68 @cindex @code{PATH} environment variable
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69 @cindex @code{HOME} environment variable
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70 In all cases, the function's @var{program} argument specifies the
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71 program to be run. An error is signaled if the file is not found or
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72 cannot be executed. If the file name is relative, the variable
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73 @code{exec-path} contains a list of directories to search. Emacs
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74 initializes @code{exec-path} when it starts up, based on the value of
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75 the environment variable @code{PATH}. The standard file name
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76 constructs, @samp{~}, @samp{.}, and @samp{..}, are interpreted as usual
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77 in @code{exec-path}, but environment variable substitutions
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78 (@samp{$HOME}, etc.) are not recognized; use
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79 @code{substitute-in-file-name} to perform them (@pxref{File Name
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80 Expansion}).
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81
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82 Each of the subprocess-creating functions has a @var{buffer-or-name}
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83 argument which specifies where the standard output from the program will
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84 go. If @var{buffer-or-name} is @code{nil}, that says to discard the
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85 output unless a filter function handles it. (@xref{Filter Functions},
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86 and @ref{Read and Print}.) Normally, you should avoid having multiple
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87 processes send output to the same buffer because their output would be
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88 intermixed randomly.
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89
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90 @cindex program arguments
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91 All three of the subprocess-creating functions have a @code{&rest}
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92 argument, @var{args}. The @var{args} must all be strings, and they are
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93 supplied to @var{program} as separate command line arguments. Wildcard
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94 characters and other shell constructs are not allowed in these strings,
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95 since they are passed directly to the specified program.
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96
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97 @strong{Please note:} The argument @var{program} contains only the
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98 name of the program; it may not contain any command-line arguments. You
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99 must use @var{args} to provide those.
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100
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101 The subprocess gets its current directory from the value of
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102 @code{default-directory} (@pxref{File Name Expansion}).
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103
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104 @cindex environment variables, subprocesses
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105 The subprocess inherits its environment from XEmacs; but you can
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106 specify overrides for it with @code{process-environment}. @xref{System
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107 Environment}.
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108
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109 @defvar exec-directory
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110 @pindex wakeup
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111 The value of this variable is the name of a directory (a string) that
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112 contains programs that come with XEmacs, that are intended for XEmacs
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113 to invoke. The program @code{wakeup} is an example of such a program;
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114 the @code{display-time} command uses it to get a reminder once per
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115 minute.
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116 @end defvar
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117
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118 @defopt exec-path
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119 The value of this variable is a list of directories to search for
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120 programs to run in subprocesses. Each element is either the name of a
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121 directory (i.e., a string), or @code{nil}, which stands for the default
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122 directory (which is the value of @code{default-directory}).
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123 @cindex program directories
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124
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125 The value of @code{exec-path} is used by @code{call-process} and
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126 @code{start-process} when the @var{program} argument is not an absolute
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127 file name.
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128 @end defopt
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129
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130 @node Synchronous Processes
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131 @section Creating a Synchronous Process
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132 @cindex synchronous subprocess
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133
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134 After a @dfn{synchronous process} is created, XEmacs waits for the
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135 process to terminate before continuing. Starting Dired is an example of
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136 this: it runs @code{ls} in a synchronous process, then modifies the
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137 output slightly. Because the process is synchronous, the entire
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138 directory listing arrives in the buffer before XEmacs tries to do
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139 anything with it.
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140
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141 While Emacs waits for the synchronous subprocess to terminate, the
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142 user can quit by typing @kbd{C-g}. The first @kbd{C-g} tries to kill
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143 the subprocess with a @code{SIGINT} signal; but it waits until the
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144 subprocess actually terminates before quitting. If during that time the
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145 user types another @kbd{C-g}, that kills the subprocess instantly with
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146 @code{SIGKILL} and quits immediately. @xref{Quitting}.
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147
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148 The synchronous subprocess functions returned @code{nil} in version
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149 18. In version 19, they return an indication of how the process
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150 terminated.
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151
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152 @defun call-process program &optional infile destination display &rest args
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153 This function calls @var{program} in a separate process and waits for
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154 it to finish.
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155
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156 The standard input for the process comes from file @var{infile} if
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157 @var{infile} is not @code{nil} and from @file{/dev/null} otherwise.
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158 The argument @var{destination} says where to put the process output.
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159 Here are the possibilities:
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160
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161 @table @asis
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162 @item a buffer
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163 Insert the output in that buffer, before point. This includes both the
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164 standard output stream and the standard error stream of the process.
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165
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166 @item a string
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167 Find or create a buffer with that name, then insert
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168 the output in that buffer, before point.
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169
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170 @item @code{t}
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171 Insert the output in the current buffer, before point.
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172
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173 @item @code{nil}
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174 Discard the output.
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175
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176 @item 0
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177 Discard the output, and return immediately without waiting
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178 for the subprocess to finish.
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179
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180 In this case, the process is not truly synchronous, since it can run in
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181 parallel with Emacs; but you can think of it as synchronous in that
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182 Emacs is essentially finished with the subprocess as soon as this
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183 function returns.
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184
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185 @item (@var{real-destination} @var{error-destination})
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186 Keep the standard output stream separate from the standard error stream;
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187 deal with the ordinary output as specified by @var{real-destination},
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188 and dispose of the error output according to @var{error-destination}.
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189 The value @code{nil} means discard it, @code{t} means mix it with the
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190 ordinary output, and a string specifies a file name to redirect error
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191 output into.
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192
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193 You can't directly specify a buffer to put the error output in; that is
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194 too difficult to implement. But you can achieve this result by sending
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195 the error output to a temporary file and then inserting the file into a
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196 buffer.
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197 @end table
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198
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199 If @var{display} is non-@code{nil}, then @code{call-process} redisplays
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200 the buffer as output is inserted. Otherwise the function does no
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201 redisplay, and the results become visible on the screen only when XEmacs
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202 redisplays that buffer in the normal course of events.
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203
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204 The remaining arguments, @var{args}, are strings that specify command
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205 line arguments for the program.
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206
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207 The value returned by @code{call-process} (unless you told it not to
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208 wait) indicates the reason for process termination. A number gives the
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209 exit status of the subprocess; 0 means success, and any other value
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210 means failure. If the process terminated with a signal,
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211 @code{call-process} returns a string describing the signal.
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212
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213 In the examples below, the buffer @samp{foo} is current.
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214
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215 @smallexample
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216 @group
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217 (call-process "pwd" nil t)
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218 @result{} nil
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219
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220 ---------- Buffer: foo ----------
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221 /usr/user/lewis/manual
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222 ---------- Buffer: foo ----------
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223 @end group
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224
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225 @group
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226 (call-process "grep" nil "bar" nil "lewis" "/etc/passwd")
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227 @result{} nil
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228
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229 ---------- Buffer: bar ----------
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230 lewis:5LTsHm66CSWKg:398:21:Bil Lewis:/user/lewis:/bin/csh
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231
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232 ---------- Buffer: bar ----------
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233 @end group
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234 @end smallexample
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235
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236 The @code{insert-directory} function contains a good example of the use
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237 of @code{call-process}:
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238
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239 @smallexample
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240 @group
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241 (call-process insert-directory-program nil t nil switches
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242 (if full-directory-p
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243 (concat (file-name-as-directory file) ".")
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244 file))
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245 @end group
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246 @end smallexample
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247 @end defun
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248
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249 @defun call-process-region start end program &optional delete destination display &rest args
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250 This function sends the text between @var{start} to @var{end} as
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251 standard input to a process running @var{program}. It deletes the text
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252 sent if @var{delete} is non-@code{nil}; this is useful when @var{buffer}
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253 is @code{t}, to insert the output in the current buffer.
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254
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255 The arguments @var{destination} and @var{display} control what to do
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256 with the output from the subprocess, and whether to update the display
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257 as it comes in. For details, see the description of
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258 @code{call-process}, above. If @var{destination} is the integer 0,
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259 @code{call-process-region} discards the output and returns @code{nil}
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260 immediately, without waiting for the subprocess to finish.
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261
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262 The remaining arguments, @var{args}, are strings that specify command
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263 line arguments for the program.
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264
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265 The return value of @code{call-process-region} is just like that of
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266 @code{call-process}: @code{nil} if you told it to return without
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267 waiting; otherwise, a number or string which indicates how the
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268 subprocess terminated.
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269
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270 In the following example, we use @code{call-process-region} to run the
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271 @code{cat} utility, with standard input being the first five characters
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272 in buffer @samp{foo} (the word @samp{input}). @code{cat} copies its
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273 standard input into its standard output. Since the argument
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274 @var{destination} is @code{t}, this output is inserted in the current
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275 buffer.
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276
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277 @smallexample
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278 @group
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279 ---------- Buffer: foo ----------
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280 input@point{}
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281 ---------- Buffer: foo ----------
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282 @end group
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283
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284 @group
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285 (call-process-region 1 6 "cat" nil t)
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286 @result{} nil
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287
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288 ---------- Buffer: foo ----------
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289 inputinput@point{}
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290 ---------- Buffer: foo ----------
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291 @end group
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292 @end smallexample
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293
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294 The @code{shell-command-on-region} command uses
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295 @code{call-process-region} like this:
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296
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297 @smallexample
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298 @group
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442
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299 (call-process-region
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300 start end
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301 shell-file-name ; @r{Name of program.}
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302 nil ; @r{Do not delete region.}
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303 buffer ; @r{Send output to @code{buffer}.}
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304 nil ; @r{No redisplay during output.}
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305 "-c" command) ; @r{Arguments for the shell.}
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306 @end group
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307 @end smallexample
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308 @end defun
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309
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310 @node MS-DOS Subprocesses
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311 @section MS-DOS Subprocesses
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312
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313 On MS-DOS, you must indicate whether the data going to and from
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314 a synchronous subprocess are text or binary. Text data requires
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315 translation between the end-of-line convention used within Emacs
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316 (a single newline character) and the convention used outside Emacs
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317 (the two-character sequence, @sc{crlf}).
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318
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319 The variable @code{binary-process-input} applies to input sent to the
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320 subprocess, and @code{binary-process-output} applies to output received
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321 from it. A non-@code{nil} value means the data is non-text; @code{nil}
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322 means the data is text, and calls for conversion.
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323
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324 @defvar binary-process-input
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325 If this variable is @code{nil}, convert newlines to @sc{crlf} sequences in
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326 the input to a synchronous subprocess.
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327 @end defvar
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328
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329 @defvar binary-process-output
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330 If this variable is @code{nil}, convert @sc{crlf} sequences to newlines in
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331 the output from a synchronous subprocess.
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332 @end defvar
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333
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334 @xref{Files and MS-DOS}, for related information.
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335
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336 @node Asynchronous Processes
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337 @section Creating an Asynchronous Process
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338 @cindex asynchronous subprocess
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339
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340 After an @dfn{asynchronous process} is created, Emacs and the Lisp
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341 program both continue running immediately. The process may thereafter
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342 run in parallel with Emacs, and the two may communicate with each other
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343 using the functions described in following sections. Here we describe
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344 how to create an asynchronous process with @code{start-process}.
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345
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346 @defun start-process name buffer-or-name program &rest args
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347 This function creates a new asynchronous subprocess and starts the
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348 program @var{program} running in it. It returns a process object that
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349 stands for the new subprocess in Lisp. The argument @var{name}
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350 specifies the name for the process object; if a process with this name
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351 already exists, then @var{name} is modified (by adding @samp{<1>}, etc.)
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352 to be unique. The buffer @var{buffer-or-name} is the buffer to
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353 associate with the process.
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354
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355 The remaining arguments, @var{args}, are strings that specify command
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356 line arguments for the program.
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357
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358 In the example below, the first process is started and runs (rather,
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359 sleeps) for 100 seconds. Meanwhile, the second process is started, and
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360 given the name @samp{my-process<1>} for the sake of uniqueness. It
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361 inserts the directory listing at the end of the buffer @samp{foo},
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362 before the first process finishes. Then it finishes, and a message to
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363 that effect is inserted in the buffer. Much later, the first process
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364 finishes, and another message is inserted in the buffer for it.
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365
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366 @smallexample
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367 @group
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368 (start-process "my-process" "foo" "sleep" "100")
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369 @result{} #<process my-process>
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370 @end group
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371
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372 @group
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373 (start-process "my-process" "foo" "ls" "-l" "/user/lewis/bin")
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374 @result{} #<process my-process<1>>
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375
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376 ---------- Buffer: foo ----------
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377 total 2
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378 lrwxrwxrwx 1 lewis 14 Jul 22 10:12 gnuemacs --> /emacs
|
|
|
379 -rwxrwxrwx 1 lewis 19 Jul 30 21:02 lemon
|
|
|
380
|
|
|
381 Process my-process<1> finished
|
|
|
382
|
|
|
383 Process my-process finished
|
|
|
384 ---------- Buffer: foo ----------
|
|
|
385 @end group
|
|
|
386 @end smallexample
|
|
|
387 @end defun
|
|
|
388
|
|
|
389 @defun start-process-shell-command name buffer-or-name command &rest command-args
|
|
|
390 This function is like @code{start-process} except that it uses a shell
|
|
|
391 to execute the specified command. The argument @var{command} is a shell
|
|
|
392 command name, and @var{command-args} are the arguments for the shell
|
|
|
393 command.
|
|
|
394 @end defun
|
|
|
395
|
|
|
396 @defvar process-connection-type
|
|
|
397 @cindex pipes
|
|
|
398 @cindex @sc{pty}s
|
|
|
399 This variable controls the type of device used to communicate with
|
|
|
400 asynchronous subprocesses. If it is non-@code{nil}, then @sc{pty}s are
|
|
|
401 used, when available. Otherwise, pipes are used.
|
|
|
402
|
|
|
403 @sc{pty}s are usually preferable for processes visible to the user, as
|
|
|
404 in Shell mode, because they allow job control (@kbd{C-c}, @kbd{C-z},
|
|
|
405 etc.) to work between the process and its children whereas pipes do not.
|
|
|
406 For subprocesses used for internal purposes by programs, it is often
|
|
|
407 better to use a pipe, because they are more efficient. In addition, the
|
|
|
408 total number of @sc{pty}s is limited on many systems and it is good not
|
|
|
409 to waste them.
|
|
|
410
|
|
|
411 The value @code{process-connection-type} is used when
|
|
|
412 @code{start-process} is called. So you can specify how to communicate
|
|
|
413 with one subprocess by binding the variable around the call to
|
|
|
414 @code{start-process}.
|
|
|
415
|
|
|
416 @smallexample
|
|
|
417 @group
|
|
|
418 (let ((process-connection-type nil)) ; @r{Use a pipe.}
|
|
|
419 (start-process @dots{}))
|
|
|
420 @end group
|
|
|
421 @end smallexample
|
|
|
422
|
|
|
423 To determine whether a given subprocess actually got a pipe or a
|
|
|
424 @sc{pty}, use the function @code{process-tty-name} (@pxref{Process
|
|
|
425 Information}).
|
|
|
426 @end defvar
|
|
|
427
|
|
|
428 @node Deleting Processes
|
|
|
429 @section Deleting Processes
|
|
|
430 @cindex deleting processes
|
|
|
431
|
|
|
432 @dfn{Deleting a process} disconnects XEmacs immediately from the
|
|
|
433 subprocess, and removes it from the list of active processes. It sends
|
|
|
434 a signal to the subprocess to make the subprocess terminate, but this is
|
|
|
435 not guaranteed to happen immediately. The process object itself
|
|
|
436 continues to exist as long as other Lisp objects point to it.
|
|
|
437
|
|
|
438 You can delete a process explicitly at any time. Processes are
|
|
|
439 deleted automatically after they terminate, but not necessarily right
|
|
|
440 away. If you delete a terminated process explicitly before it is
|
|
|
441 deleted automatically, no harm results.
|
|
|
442
|
|
|
443 @defvar delete-exited-processes
|
|
|
444 This variable controls automatic deletion of processes that have
|
|
|
445 terminated (due to calling @code{exit} or to a signal). If it is
|
|
|
446 @code{nil}, then they continue to exist until the user runs
|
|
|
447 @code{list-processes}. Otherwise, they are deleted immediately after
|
|
|
448 they exit.
|
|
|
449 @end defvar
|
|
|
450
|
|
|
451 @defun delete-process name
|
|
|
452 This function deletes the process associated with @var{name}, killing it
|
|
|
453 with a @code{SIGHUP} signal. The argument @var{name} may be a process,
|
|
|
454 the name of a process, a buffer, or the name of a buffer.
|
|
|
455
|
|
|
456 @smallexample
|
|
|
457 @group
|
|
|
458 (delete-process "*shell*")
|
|
|
459 @result{} nil
|
|
|
460 @end group
|
|
|
461 @end smallexample
|
|
|
462 @end defun
|
|
|
463
|
|
|
464 @defun process-kill-without-query process &optional require-query-p
|
|
|
465 This function declares that XEmacs need not query the user if
|
|
|
466 @var{process} is still running when XEmacs is exited. The process will
|
|
|
467 be deleted silently. If @var{require-query-p} is non-@code{nil},
|
|
|
468 then XEmacs @emph{will} query the user (this is the default). The
|
|
|
469 return value is @code{t} if a query was formerly required, and
|
|
|
470 @code{nil} otherwise.
|
|
|
471
|
|
|
472 @smallexample
|
|
|
473 @group
|
|
|
474 (process-kill-without-query (get-process "shell"))
|
|
|
475 @result{} t
|
|
|
476 @end group
|
|
|
477 @end smallexample
|
|
|
478 @end defun
|
|
|
479
|
|
|
480 @node Process Information
|
|
|
481 @section Process Information
|
|
|
482
|
|
|
483 Several functions return information about processes.
|
|
|
484 @code{list-processes} is provided for interactive use.
|
|
|
485
|
|
|
486 @deffn Command list-processes
|
|
|
487 This command displays a listing of all living processes. In addition,
|
|
|
488 it finally deletes any process whose status was @samp{Exited} or
|
|
|
489 @samp{Signaled}. It returns @code{nil}.
|
|
|
490 @end deffn
|
|
|
491
|
|
|
492 @defun process-list
|
|
|
493 This function returns a list of all processes that have not been deleted.
|
|
|
494
|
|
|
495 @smallexample
|
|
|
496 @group
|
|
|
497 (process-list)
|
|
|
498 @result{} (#<process display-time> #<process shell>)
|
|
|
499 @end group
|
|
|
500 @end smallexample
|
|
|
501 @end defun
|
|
|
502
|
|
|
503 @defun get-process name
|
|
|
504 This function returns the process named @var{name}, or @code{nil} if
|
|
|
505 there is none. An error is signaled if @var{name} is not a string.
|
|
|
506
|
|
|
507 @smallexample
|
|
|
508 @group
|
|
|
509 (get-process "shell")
|
|
|
510 @result{} #<process shell>
|
|
|
511 @end group
|
|
|
512 @end smallexample
|
|
|
513 @end defun
|
|
|
514
|
|
|
515 @defun process-command process
|
|
|
516 This function returns the command that was executed to start
|
|
|
517 @var{process}. This is a list of strings, the first string being the
|
|
|
518 program executed and the rest of the strings being the arguments that
|
|
|
519 were given to the program.
|
|
|
520
|
|
|
521 @smallexample
|
|
|
522 @group
|
|
|
523 (process-command (get-process "shell"))
|
|
|
524 @result{} ("/bin/csh" "-i")
|
|
|
525 @end group
|
|
|
526 @end smallexample
|
|
|
527 @end defun
|
|
|
528
|
|
|
529 @defun process-id process
|
|
|
530 This function returns the @sc{pid} of @var{process}. This is an
|
|
|
531 integer that distinguishes the process @var{process} from all other
|
|
|
532 processes running on the same computer at the current time. The
|
|
|
533 @sc{pid} of a process is chosen by the operating system kernel when the
|
|
|
534 process is started and remains constant as long as the process exists.
|
|
|
535 @end defun
|
|
|
536
|
|
|
537 @defun process-name process
|
|
|
538 This function returns the name of @var{process}.
|
|
|
539 @end defun
|
|
|
540
|
|
|
541 @defun process-status process-name
|
|
|
542 This function returns the status of @var{process-name} as a symbol.
|
|
|
543 The argument @var{process-name} must be a process, a buffer, a
|
|
|
544 process name (string) or a buffer name (string).
|
|
|
545
|
|
|
546 The possible values for an actual subprocess are:
|
|
|
547
|
|
|
548 @table @code
|
|
|
549 @item run
|
|
|
550 for a process that is running.
|
|
|
551 @item stop
|
|
|
552 for a process that is stopped but continuable.
|
|
|
553 @item exit
|
|
|
554 for a process that has exited.
|
|
|
555 @item signal
|
|
|
556 for a process that has received a fatal signal.
|
|
|
557 @item open
|
|
|
558 for a network connection that is open.
|
|
|
559 @item closed
|
|
|
560 for a network connection that is closed. Once a connection
|
|
|
561 is closed, you cannot reopen it, though you might be able to open
|
|
|
562 a new connection to the same place.
|
|
|
563 @item nil
|
|
|
564 if @var{process-name} is not the name of an existing process.
|
|
|
565 @end table
|
|
|
566
|
|
|
567 @smallexample
|
|
|
568 @group
|
|
|
569 (process-status "shell")
|
|
|
570 @result{} run
|
|
|
571 @end group
|
|
|
572 @group
|
|
|
573 (process-status (get-buffer "*shell*"))
|
|
|
574 @result{} run
|
|
|
575 @end group
|
|
|
576 @group
|
|
|
577 x
|
|
|
578 @result{} #<process xx<1>>
|
|
|
579 (process-status x)
|
|
|
580 @result{} exit
|
|
|
581 @end group
|
|
|
582 @end smallexample
|
|
|
583
|
|
|
584 For a network connection, @code{process-status} returns one of the symbols
|
|
|
585 @code{open} or @code{closed}. The latter means that the other side
|
|
|
586 closed the connection, or XEmacs did @code{delete-process}.
|
|
|
587
|
|
|
588 In earlier Emacs versions (prior to version 19), the status of a network
|
|
|
589 connection was @code{run} if open, and @code{exit} if closed.
|
|
|
590 @end defun
|
|
|
591
|
|
|
592 @defun process-kill-without-query-p process
|
|
|
593 This function returns whether @var{process} will be killed without
|
|
|
594 querying the user, if it is running when XEmacs is exited. The default
|
|
|
595 value is @code{nil}.
|
|
|
596 @end defun
|
|
|
597
|
|
|
598 @defun process-exit-status process
|
|
|
599 This function returns the exit status of @var{process} or the signal
|
|
|
600 number that killed it. (Use the result of @code{process-status} to
|
|
|
601 determine which of those it is.) If @var{process} has not yet
|
|
|
602 terminated, the value is 0.
|
|
|
603 @end defun
|
|
|
604
|
|
|
605 @defun process-tty-name process
|
|
|
606 This function returns the terminal name that @var{process} is using for
|
|
|
607 its communication with Emacs---or @code{nil} if it is using pipes
|
|
|
608 instead of a terminal (see @code{process-connection-type} in
|
|
|
609 @ref{Asynchronous Processes}).
|
|
|
610 @end defun
|
|
|
611
|
|
|
612 @node Input to Processes
|
|
|
613 @section Sending Input to Processes
|
|
|
614 @cindex process input
|
|
|
615
|
|
|
616 Asynchronous subprocesses receive input when it is sent to them by
|
|
|
617 XEmacs, which is done with the functions in this section. You must
|
|
|
618 specify the process to send input to, and the input data to send. The
|
|
|
619 data appears on the ``standard input'' of the subprocess.
|
|
|
620
|
|
|
621 Some operating systems have limited space for buffered input in a
|
|
|
622 @sc{pty}. On these systems, Emacs sends an @sc{eof} periodically amidst
|
|
|
623 the other characters, to force them through. For most programs,
|
|
|
624 these @sc{eof}s do no harm.
|
|
|
625
|
|
|
626 @defun process-send-string process-name string
|
|
|
627 This function sends @var{process-name} the contents of @var{string} as
|
|
|
628 standard input. The argument @var{process-name} must be a process or
|
|
|
629 the name of a process. If it is @code{nil}, the current buffer's
|
|
|
630 process is used.
|
|
|
631
|
|
|
632 The function returns @code{nil}.
|
|
|
633
|
|
|
634 @smallexample
|
|
|
635 @group
|
|
|
636 (process-send-string "shell<1>" "ls\n")
|
|
|
637 @result{} nil
|
|
|
638 @end group
|
|
|
639
|
|
|
640
|
|
|
641 @group
|
|
|
642 ---------- Buffer: *shell* ----------
|
|
|
643 ...
|
|
|
644 introduction.texi syntax-tables.texi~
|
|
|
645 introduction.texi~ text.texi
|
|
|
646 introduction.txt text.texi~
|
|
|
647 ...
|
|
|
648 ---------- Buffer: *shell* ----------
|
|
|
649 @end group
|
|
|
650 @end smallexample
|
|
|
651 @end defun
|
|
|
652
|
|
|
653 @deffn Command process-send-region process-name start end
|
|
|
654 This function sends the text in the region defined by @var{start} and
|
|
|
655 @var{end} as standard input to @var{process-name}, which is a process or
|
|
|
656 a process name. (If it is @code{nil}, the current buffer's process is
|
|
|
657 used.)
|
|
|
658
|
|
|
659 An error is signaled unless both @var{start} and @var{end} are
|
|
|
660 integers or markers that indicate positions in the current buffer. (It
|
|
|
661 is unimportant which number is larger.)
|
|
|
662 @end deffn
|
|
|
663
|
|
|
664 @defun process-send-eof &optional process-name
|
|
|
665 This function makes @var{process-name} see an end-of-file in its
|
|
|
666 input. The @sc{eof} comes after any text already sent to it.
|
|
|
667
|
|
|
668 If @var{process-name} is not supplied, or if it is @code{nil}, then
|
|
|
669 this function sends the @sc{eof} to the current buffer's process. An
|
|
|
670 error is signaled if the current buffer has no process.
|
|
|
671
|
|
|
672 The function returns @var{process-name}.
|
|
|
673
|
|
|
674 @smallexample
|
|
|
675 @group
|
|
|
676 (process-send-eof "shell")
|
|
|
677 @result{} "shell"
|
|
|
678 @end group
|
|
|
679 @end smallexample
|
|
|
680 @end defun
|
|
|
681
|
|
|
682 @node Signals to Processes
|
|
|
683 @section Sending Signals to Processes
|
|
|
684 @cindex process signals
|
|
|
685 @cindex sending signals
|
|
|
686 @cindex signals
|
|
|
687
|
|
|
688 @dfn{Sending a signal} to a subprocess is a way of interrupting its
|
|
|
689 activities. There are several different signals, each with its own
|
|
|
690 meaning. The set of signals and their names is defined by the operating
|
|
|
691 system. For example, the signal @code{SIGINT} means that the user has
|
|
|
692 typed @kbd{C-c}, or that some analogous thing has happened.
|
|
|
693
|
|
|
694 Each signal has a standard effect on the subprocess. Most signals
|
|
|
695 kill the subprocess, but some stop or resume execution instead. Most
|
|
|
696 signals can optionally be handled by programs; if the program handles
|
|
|
697 the signal, then we can say nothing in general about its effects.
|
|
|
698
|
|
|
699 The set of signals and their names is defined by the operating system;
|
|
|
700 XEmacs has facilities for sending only a few of the signals that are
|
|
|
701 defined. XEmacs can send signals only to its own subprocesses.
|
|
|
702
|
|
|
703 You can send signals explicitly by calling the functions in this
|
|
|
704 section. XEmacs also sends signals automatically at certain times:
|
|
|
705 killing a buffer sends a @code{SIGHUP} signal to all its associated
|
|
|
706 processes; killing XEmacs sends a @code{SIGHUP} signal to all remaining
|
|
442
|
707 processes. (@code{SIGHUP} is a signal that indicates that the
|
|
|
708 connection between the user and the process is broken, for example if a
|
|
|
709 connection via a telephone line is hung up.)
|
|
0
|
710
|
|
|
711 Each of the signal-sending functions takes two optional arguments:
|
|
442
|
712 @var{process} and @var{current-group}.
|
|
0
|
713
|
|
442
|
714 The argument @var{process} must be either a process or a buffer,
|
|
|
715 the name of one, or @code{nil}. If it is @code{nil}, the process
|
|
|
716 defaults to the process associated with the current buffer. An error is
|
|
|
717 signaled if @var{process} does not identify a process.
|
|
0
|
718
|
|
|
719 The argument @var{current-group} is a flag that makes a difference
|
|
|
720 when you are running a job-control shell as an XEmacs subprocess. If it
|
|
442
|
721 is non-@code{nil}, then the signal is sent to the current foreground
|
|
|
722 process group of the terminal that XEmacs uses to communicate with the
|
|
|
723 subprocess. If the process is a job-control shell, this means the
|
|
|
724 shell's current subjob. If it is @code{nil}, the signal is sent to the
|
|
|
725 process group of the immediate subprocess of XEmacs. If the subprocess
|
|
|
726 is a job-control shell, this is the shell itself.
|
|
0
|
727
|
|
|
728 The flag @var{current-group} has no effect when a pipe is used to
|
|
|
729 communicate with the subprocess, because the operating system does not
|
|
|
730 support the distinction in the case of pipes. For the same reason,
|
|
|
731 job-control shells won't work when a pipe is used. See
|
|
|
732 @code{process-connection-type} in @ref{Asynchronous Processes}.
|
|
|
733
|
|
442
|
734 Some of the functions below take a @var{signal} argument, which
|
|
|
735 identifies a signal to be sent. It must be either an integer or a
|
|
|
736 symbol which names the signal, like @code{SIGSEGV}.
|
|
|
737
|
|
|
738 @defun process-send-signal signal &optional process current-group
|
|
|
739 This function sends the signal @var{signal} to the process @var{process}.
|
|
|
740 The following functions can be implemented in terms of
|
|
|
741 @code{process-send-signal}.
|
|
0
|
742 @end defun
|
|
|
743
|
|
442
|
744 @defun interrupt-process &optional process current-group
|
|
|
745 This function interrupts the process @var{process} by sending the signal
|
|
|
746 @code{SIGINT}. Outside of XEmacs, typing the ``interrupt character''
|
|
|
747 (normally @kbd{C-c}) sends this signal. When the argument
|
|
|
748 @var{current-group} is non-@code{nil}, you can think of this function as
|
|
|
749 ``typing @kbd{C-c}'' on the terminal by which XEmacs talks to the
|
|
|
750 subprocess.
|
|
|
751 @end defun
|
|
|
752
|
|
|
753 @defun kill-process &optional process current-group
|
|
|
754 This function kills the process @var{process} by sending the
|
|
0
|
755 signal @code{SIGKILL}. This signal kills the subprocess immediately,
|
|
|
756 and cannot be handled by the subprocess.
|
|
|
757 @end defun
|
|
|
758
|
|
442
|
759 @defun quit-process &optional process current-group
|
|
0
|
760 This function sends the signal @code{SIGQUIT} to the process
|
|
442
|
761 @var{process}. This signal is the one sent by the ``quit
|
|
|
762 character'' (usually @kbd{C-\}) when you are not inside XEmacs.
|
|
0
|
763 @end defun
|
|
|
764
|
|
442
|
765 @defun stop-process &optional process current-group
|
|
|
766 This function stops the process @var{process} by sending the
|
|
0
|
767 signal @code{SIGTSTP}. Use @code{continue-process} to resume its
|
|
|
768 execution.
|
|
|
769
|
|
|
770 On systems with job control, the ``stop character'' (usually @kbd{C-z})
|
|
|
771 sends this signal (outside of XEmacs). When @var{current-group} is
|
|
|
772 non-@code{nil}, you can think of this function as ``typing @kbd{C-z}''
|
|
|
773 on the terminal XEmacs uses to communicate with the subprocess.
|
|
|
774 @end defun
|
|
|
775
|
|
442
|
776 @defun continue-process &optional process current-group
|
|
0
|
777 This function resumes execution of the process @var{process} by sending
|
|
442
|
778 it the signal @code{SIGCONT}. This presumes that @var{process} was
|
|
0
|
779 stopped previously.
|
|
|
780 @end defun
|
|
|
781
|
|
|
782 @defun signal-process pid signal
|
|
442
|
783 This function sends a signal to the process with process id @var{pid},
|
|
|
784 which need not be a child of XEmacs. The argument @var{signal}
|
|
|
785 specifies which signal to send.
|
|
0
|
786 @end defun
|
|
|
787
|
|
|
788 @node Output from Processes
|
|
|
789 @section Receiving Output from Processes
|
|
|
790 @cindex process output
|
|
|
791 @cindex output from processes
|
|
|
792
|
|
|
793 There are two ways to receive the output that a subprocess writes to
|
|
|
794 its standard output stream. The output can be inserted in a buffer,
|
|
|
795 which is called the associated buffer of the process, or a function
|
|
|
796 called the @dfn{filter function} can be called to act on the output. If
|
|
|
797 the process has no buffer and no filter function, its output is
|
|
|
798 discarded.
|
|
|
799
|
|
|
800 @menu
|
|
|
801 * Process Buffers:: If no filter, output is put in a buffer.
|
|
|
802 * Filter Functions:: Filter functions accept output from the process.
|
|
|
803 * Accepting Output:: Explicitly permitting subprocess output.
|
|
|
804 Waiting for subprocess output.
|
|
|
805 @end menu
|
|
|
806
|
|
|
807 @node Process Buffers
|
|
|
808 @subsection Process Buffers
|
|
|
809
|
|
|
810 A process can (and usually does) have an @dfn{associated buffer},
|
|
|
811 which is an ordinary Emacs buffer that is used for two purposes: storing
|
|
|
812 the output from the process, and deciding when to kill the process. You
|
|
|
813 can also use the buffer to identify a process to operate on, since in
|
|
|
814 normal practice only one process is associated with any given buffer.
|
|
|
815 Many applications of processes also use the buffer for editing input to
|
|
|
816 be sent to the process, but this is not built into XEmacs Lisp.
|
|
|
817
|
|
|
818 Unless the process has a filter function (@pxref{Filter Functions}),
|
|
|
819 its output is inserted in the associated buffer. The position to insert
|
|
|
820 the output is determined by the @code{process-mark}, which is then
|
|
|
821 updated to point to the end of the text just inserted. Usually, but not
|
|
|
822 always, the @code{process-mark} is at the end of the buffer.
|
|
|
823
|
|
|
824 @defun process-buffer process
|
|
|
825 This function returns the associated buffer of the process
|
|
|
826 @var{process}.
|
|
|
827
|
|
|
828 @smallexample
|
|
|
829 @group
|
|
|
830 (process-buffer (get-process "shell"))
|
|
|
831 @result{} #<buffer *shell*>
|
|
|
832 @end group
|
|
|
833 @end smallexample
|
|
|
834 @end defun
|
|
|
835
|
|
|
836 @defun process-mark process
|
|
|
837 This function returns the process marker for @var{process}, which is the
|
|
|
838 marker that says where to insert output from the process.
|
|
|
839
|
|
|
840 If @var{process} does not have a buffer, @code{process-mark} returns a
|
|
|
841 marker that points nowhere.
|
|
|
842
|
|
|
843 Insertion of process output in a buffer uses this marker to decide where
|
|
|
844 to insert, and updates it to point after the inserted text. That is why
|
|
|
845 successive batches of output are inserted consecutively.
|
|
|
846
|
|
|
847 Filter functions normally should use this marker in the same fashion
|
|
|
848 as is done by direct insertion of output in the buffer. A good
|
|
|
849 example of a filter function that uses @code{process-mark} is found at
|
|
|
850 the end of the following section.
|
|
|
851
|
|
|
852 When the user is expected to enter input in the process buffer for
|
|
|
853 transmission to the process, the process marker is useful for
|
|
|
854 distinguishing the new input from previous output.
|
|
|
855 @end defun
|
|
|
856
|
|
|
857 @defun set-process-buffer process buffer
|
|
|
858 This function sets the buffer associated with @var{process} to
|
|
|
859 @var{buffer}. If @var{buffer} is @code{nil}, the process becomes
|
|
|
860 associated with no buffer.
|
|
|
861 @end defun
|
|
|
862
|
|
|
863 @defun get-buffer-process buffer-or-name
|
|
|
864 This function returns the process associated with @var{buffer-or-name}.
|
|
|
865 If there are several processes associated with it, then one is chosen.
|
|
|
866 (Presently, the one chosen is the one most recently created.) It is
|
|
|
867 usually a bad idea to have more than one process associated with the
|
|
|
868 same buffer.
|
|
|
869
|
|
|
870 @smallexample
|
|
|
871 @group
|
|
|
872 (get-buffer-process "*shell*")
|
|
|
873 @result{} #<process shell>
|
|
|
874 @end group
|
|
|
875 @end smallexample
|
|
|
876
|
|
|
877 Killing the process's buffer deletes the process, which kills the
|
|
|
878 subprocess with a @code{SIGHUP} signal (@pxref{Signals to Processes}).
|
|
|
879 @end defun
|
|
|
880
|
|
|
881 @node Filter Functions
|
|
|
882 @subsection Process Filter Functions
|
|
|
883 @cindex filter function
|
|
|
884 @cindex process filter
|
|
|
885
|
|
|
886 A process @dfn{filter function} is a function that receives the
|
|
|
887 standard output from the associated process. If a process has a filter,
|
|
|
888 then @emph{all} output from that process is passed to the filter. The
|
|
|
889 process buffer is used directly for output from the process only when
|
|
|
890 there is no filter.
|
|
|
891
|
|
|
892 A filter function must accept two arguments: the associated process and
|
|
|
893 a string, which is the output. The function is then free to do whatever it
|
|
|
894 chooses with the output.
|
|
|
895
|
|
|
896 A filter function runs only while XEmacs is waiting (e.g., for terminal
|
|
|
897 input, or for time to elapse, or for process output). This avoids the
|
|
|
898 timing errors that could result from running filters at random places in
|
|
|
899 the middle of other Lisp programs. You may explicitly cause Emacs to
|
|
|
900 wait, so that filter functions will run, by calling @code{sit-for} or
|
|
|
901 @code{sleep-for} (@pxref{Waiting}), or @code{accept-process-output}
|
|
|
902 (@pxref{Accepting Output}). Emacs is also waiting when the command loop
|
|
|
903 is reading input.
|
|
|
904
|
|
|
905 Quitting is normally inhibited within a filter function---otherwise,
|
|
|
906 the effect of typing @kbd{C-g} at command level or to quit a user
|
|
|
907 command would be unpredictable. If you want to permit quitting inside a
|
|
|
908 filter function, bind @code{inhibit-quit} to @code{nil}.
|
|
|
909 @xref{Quitting}.
|
|
|
910
|
|
|
911 If an error happens during execution of a filter function, it is
|
|
|
912 caught automatically, so that it doesn't stop the execution of whatever
|
|
|
913 program was running when the filter function was started. However, if
|
|
|
914 @code{debug-on-error} is non-@code{nil}, the error-catching is turned
|
|
|
915 off. This makes it possible to use the Lisp debugger to debug the
|
|
|
916 filter function. @xref{Debugger}.
|
|
|
917
|
|
|
918 Many filter functions sometimes or always insert the text in the
|
|
|
919 process's buffer, mimicking the actions of XEmacs when there is no
|
|
|
920 filter. Such filter functions need to use @code{set-buffer} in order to
|
|
|
921 be sure to insert in that buffer. To avoid setting the current buffer
|
|
|
922 semipermanently, these filter functions must use @code{unwind-protect}
|
|
|
923 to make sure to restore the previous current buffer. They should also
|
|
|
924 update the process marker, and in some cases update the value of point.
|
|
|
925 Here is how to do these things:
|
|
|
926
|
|
|
927 @smallexample
|
|
|
928 @group
|
|
|
929 (defun ordinary-insertion-filter (proc string)
|
|
|
930 (let ((old-buffer (current-buffer)))
|
|
|
931 (unwind-protect
|
|
|
932 (let (moving)
|
|
|
933 (set-buffer (process-buffer proc))
|
|
|
934 (setq moving (= (point) (process-mark proc)))
|
|
|
935 @end group
|
|
|
936 @group
|
|
|
937 (save-excursion
|
|
|
938 ;; @r{Insert the text, moving the process-marker.}
|
|
|
939 (goto-char (process-mark proc))
|
|
|
940 (insert string)
|
|
|
941 (set-marker (process-mark proc) (point)))
|
|
|
942 (if moving (goto-char (process-mark proc))))
|
|
|
943 (set-buffer old-buffer))))
|
|
|
944 @end group
|
|
|
945 @end smallexample
|
|
|
946
|
|
|
947 @noindent
|
|
|
948 The reason to use an explicit @code{unwind-protect} rather than letting
|
|
|
949 @code{save-excursion} restore the current buffer is so as to preserve
|
|
|
950 the change in point made by @code{goto-char}.
|
|
|
951
|
|
|
952 To make the filter force the process buffer to be visible whenever new
|
|
|
953 text arrives, insert the following line just before the
|
|
|
954 @code{unwind-protect}:
|
|
|
955
|
|
|
956 @smallexample
|
|
|
957 (display-buffer (process-buffer proc))
|
|
|
958 @end smallexample
|
|
|
959
|
|
|
960 To force point to move to the end of the new output no matter where
|
|
|
961 it was previously, eliminate the variable @code{moving} and call
|
|
|
962 @code{goto-char} unconditionally.
|
|
|
963
|
|
|
964 In earlier Emacs versions, every filter function that did regexp
|
|
|
965 searching or matching had to explicitly save and restore the match data.
|
|
|
966 Now Emacs does this automatically; filter functions never need to do it
|
|
|
967 explicitly. @xref{Match Data}.
|
|
|
968
|
|
|
969 A filter function that writes the output into the buffer of the
|
|
|
970 process should check whether the buffer is still alive. If it tries to
|
|
|
971 insert into a dead buffer, it will get an error. If the buffer is dead,
|
|
|
972 @code{(buffer-name (process-buffer @var{process}))} returns @code{nil}.
|
|
|
973
|
|
|
974 The output to the function may come in chunks of any size. A program
|
|
|
975 that produces the same output twice in a row may send it as one batch
|
|
|
976 of 200 characters one time, and five batches of 40 characters the next.
|
|
|
977
|
|
|
978 @defun set-process-filter process filter
|
|
|
979 This function gives @var{process} the filter function @var{filter}. If
|
|
|
980 @var{filter} is @code{nil}, then the process will have no filter. If
|
|
|
981 @var{filter} is @code{t}, then no output from the process will be
|
|
|
982 accepted until the filter is changed. (Output received during this
|
|
|
983 time is not discarded, but is queued, and will be processed as soon
|
|
|
984 as the filter is changed.)
|
|
|
985 @end defun
|
|
|
986
|
|
|
987 @defun process-filter process
|
|
|
988 This function returns the filter function of @var{process}, or @code{nil}
|
|
|
989 if it has none. @code{t} means that output processing has been stopped.
|
|
|
990 @end defun
|
|
|
991
|
|
|
992 Here is an example of use of a filter function:
|
|
|
993
|
|
|
994 @smallexample
|
|
|
995 @group
|
|
|
996 (defun keep-output (process output)
|
|
|
997 (setq kept (cons output kept)))
|
|
|
998 @result{} keep-output
|
|
|
999 @end group
|
|
|
1000 @group
|
|
|
1001 (setq kept nil)
|
|
|
1002 @result{} nil
|
|
|
1003 @end group
|
|
|
1004 @group
|
|
|
1005 (set-process-filter (get-process "shell") 'keep-output)
|
|
|
1006 @result{} keep-output
|
|
|
1007 @end group
|
|
|
1008 @group
|
|
|
1009 (process-send-string "shell" "ls ~/other\n")
|
|
|
1010 @result{} nil
|
|
|
1011 kept
|
|
|
1012 @result{} ("lewis@@slug[8] % "
|
|
|
1013 @end group
|
|
|
1014 @group
|
|
|
1015 "FINAL-W87-SHORT.MSS backup.otl kolstad.mss~
|
|
|
1016 address.txt backup.psf kolstad.psf
|
|
|
1017 backup.bib~ david.mss resume-Dec-86.mss~
|
|
|
1018 backup.err david.psf resume-Dec.psf
|
|
|
1019 backup.mss dland syllabus.mss
|
|
|
1020 "
|
|
|
1021 "#backups.mss# backup.mss~ kolstad.mss
|
|
|
1022 ")
|
|
|
1023 @end group
|
|
|
1024 @end smallexample
|
|
|
1025
|
|
|
1026 @ignore @c The code in this example doesn't show the right way to do things.
|
|
|
1027 Here is another, more realistic example, which demonstrates how to use
|
|
|
1028 the process mark to do insertion in the same fashion as is done when
|
|
|
1029 there is no filter function:
|
|
|
1030
|
|
|
1031 @smallexample
|
|
|
1032 @group
|
|
|
1033 ;; @r{Insert input in the buffer specified by @code{my-shell-buffer}}
|
|
|
1034 ;; @r{and make sure that buffer is shown in some window.}
|
|
|
1035 (defun my-process-filter (proc str)
|
|
|
1036 (let ((cur (selected-window))
|
|
|
1037 (pop-up-windows t))
|
|
|
1038 (pop-to-buffer my-shell-buffer)
|
|
|
1039 @end group
|
|
|
1040 @group
|
|
|
1041 (goto-char (point-max))
|
|
|
1042 (insert str)
|
|
|
1043 (set-marker (process-mark proc) (point-max))
|
|
|
1044 (select-window cur)))
|
|
|
1045 @end group
|
|
|
1046 @end smallexample
|
|
|
1047 @end ignore
|
|
|
1048
|
|
|
1049 @node Accepting Output
|
|
|
1050 @subsection Accepting Output from Processes
|
|
|
1051
|
|
|
1052 Output from asynchronous subprocesses normally arrives only while
|
|
|
1053 XEmacs is waiting for some sort of external event, such as elapsed time
|
|
|
1054 or terminal input. Occasionally it is useful in a Lisp program to
|
|
|
1055 explicitly permit output to arrive at a specific point, or even to wait
|
|
|
1056 until output arrives from a process.
|
|
|
1057
|
|
|
1058 @defun accept-process-output &optional process seconds millisec
|
|
|
1059 This function allows XEmacs to read pending output from processes. The
|
|
|
1060 output is inserted in the associated buffers or given to their filter
|
|
|
1061 functions. If @var{process} is non-@code{nil} then this function does
|
|
|
1062 not return until some output has been received from @var{process}.
|
|
|
1063
|
|
|
1064 @c Emacs 19 feature
|
|
|
1065 The arguments @var{seconds} and @var{millisec} let you specify timeout
|
|
|
1066 periods. The former specifies a period measured in seconds and the
|
|
|
1067 latter specifies one measured in milliseconds. The two time periods
|
|
|
1068 thus specified are added together, and @code{accept-process-output}
|
|
|
1069 returns after that much time whether or not there has been any
|
|
|
1070 subprocess output. Note that @var{seconds} is allowed to be a
|
|
|
1071 floating-point number; thus, there is no need to ever use
|
|
|
1072 @var{millisec}. (It is retained for compatibility purposes.)
|
|
|
1073 @ignore Not in XEmacs
|
|
|
1074
|
|
|
1075 The argument @var{seconds} need not be an integer. If it is a floating
|
|
|
1076 point number, this function waits for a fractional number of seconds.
|
|
|
1077 Some systems support only a whole number of seconds; on these systems,
|
|
|
1078 @var{seconds} is rounded down. If the system doesn't support waiting
|
|
|
1079 fractions of a second, you get an error if you specify nonzero
|
|
|
1080 @var{millisec}.
|
|
|
1081
|
|
|
1082 Not all operating systems support waiting periods other than multiples
|
|
|
1083 of a second; on those that do not, you get an error if you specify
|
|
|
1084 nonzero @var{millisec}.
|
|
|
1085 @end ignore
|
|
|
1086
|
|
|
1087 The function @code{accept-process-output} returns non-@code{nil} if it
|
|
|
1088 did get some output, or @code{nil} if the timeout expired before output
|
|
|
1089 arrived.
|
|
|
1090 @end defun
|
|
|
1091
|
|
|
1092 @node Sentinels
|
|
|
1093 @section Sentinels: Detecting Process Status Changes
|
|
|
1094 @cindex process sentinel
|
|
|
1095 @cindex sentinel
|
|
|
1096
|
|
|
1097 A @dfn{process sentinel} is a function that is called whenever the
|
|
|
1098 associated process changes status for any reason, including signals
|
|
|
1099 (whether sent by XEmacs or caused by the process's own actions) that
|
|
|
1100 terminate, stop, or continue the process. The process sentinel is also
|
|
|
1101 called if the process exits. The sentinel receives two arguments: the
|
|
|
1102 process for which the event occurred, and a string describing the type
|
|
|
1103 of event.
|
|
|
1104
|
|
|
1105 The string describing the event looks like one of the following:
|
|
|
1106
|
|
|
1107 @itemize @bullet
|
|
442
|
1108 @item
|
|
0
|
1109 @code{"finished\n"}.
|
|
|
1110
|
|
|
1111 @item
|
|
|
1112 @code{"exited abnormally with code @var{exitcode}\n"}.
|
|
|
1113
|
|
|
1114 @item
|
|
|
1115 @code{"@var{name-of-signal}\n"}.
|
|
|
1116
|
|
|
1117 @item
|
|
|
1118 @code{"@var{name-of-signal} (core dumped)\n"}.
|
|
|
1119 @end itemize
|
|
|
1120
|
|
|
1121 A sentinel runs only while XEmacs is waiting (e.g., for terminal input,
|
|
|
1122 or for time to elapse, or for process output). This avoids the timing
|
|
|
1123 errors that could result from running them at random places in the
|
|
|
1124 middle of other Lisp programs. A program can wait, so that sentinels
|
|
|
1125 will run, by calling @code{sit-for} or @code{sleep-for}
|
|
|
1126 (@pxref{Waiting}), or @code{accept-process-output} (@pxref{Accepting
|
|
|
1127 Output}). Emacs is also waiting when the command loop is reading input.
|
|
|
1128
|
|
|
1129 Quitting is normally inhibited within a sentinel---otherwise, the
|
|
|
1130 effect of typing @kbd{C-g} at command level or to quit a user command
|
|
|
1131 would be unpredictable. If you want to permit quitting inside a
|
|
|
1132 sentinel, bind @code{inhibit-quit} to @code{nil}. @xref{Quitting}.
|
|
|
1133
|
|
|
1134 A sentinel that writes the output into the buffer of the process
|
|
|
1135 should check whether the buffer is still alive. If it tries to insert
|
|
|
1136 into a dead buffer, it will get an error. If the buffer is dead,
|
|
|
1137 @code{(buffer-name (process-buffer @var{process}))} returns @code{nil}.
|
|
|
1138
|
|
|
1139 If an error happens during execution of a sentinel, it is caught
|
|
|
1140 automatically, so that it doesn't stop the execution of whatever
|
|
|
1141 programs was running when the sentinel was started. However, if
|
|
|
1142 @code{debug-on-error} is non-@code{nil}, the error-catching is turned
|
|
|
1143 off. This makes it possible to use the Lisp debugger to debug the
|
|
|
1144 sentinel. @xref{Debugger}.
|
|
|
1145
|
|
|
1146 In earlier Emacs versions, every sentinel that did regexp searching or
|
|
|
1147 matching had to explicitly save and restore the match data. Now Emacs
|
|
|
1148 does this automatically; sentinels never need to do it explicitly.
|
|
|
1149 @xref{Match Data}.
|
|
|
1150
|
|
|
1151 @defun set-process-sentinel process sentinel
|
|
|
1152 This function associates @var{sentinel} with @var{process}. If
|
|
|
1153 @var{sentinel} is @code{nil}, then the process will have no sentinel.
|
|
|
1154 The default behavior when there is no sentinel is to insert a message in
|
|
|
1155 the process's buffer when the process status changes.
|
|
|
1156
|
|
|
1157 @smallexample
|
|
|
1158 @group
|
|
|
1159 (defun msg-me (process event)
|
|
|
1160 (princ
|
|
|
1161 (format "Process: %s had the event `%s'" process event)))
|
|
|
1162 (set-process-sentinel (get-process "shell") 'msg-me)
|
|
|
1163 @result{} msg-me
|
|
|
1164 @end group
|
|
|
1165 @group
|
|
|
1166 (kill-process (get-process "shell"))
|
|
|
1167 @print{} Process: #<process shell> had the event `killed'
|
|
|
1168 @result{} #<process shell>
|
|
|
1169 @end group
|
|
|
1170 @end smallexample
|
|
|
1171 @end defun
|
|
|
1172
|
|
|
1173 @defun process-sentinel process
|
|
|
1174 This function returns the sentinel of @var{process}, or @code{nil} if it
|
|
|
1175 has none.
|
|
|
1176 @end defun
|
|
|
1177
|
|
|
1178 @defun waiting-for-user-input-p
|
|
|
1179 While a sentinel or filter function is running, this function returns
|
|
|
1180 non-@code{nil} if XEmacs was waiting for keyboard input from the user at
|
|
|
1181 the time the sentinel or filter function was called, @code{nil} if it
|
|
|
1182 was not.
|
|
|
1183 @end defun
|
|
|
1184
|
|
|
1185 @c XEmacs feature
|
|
|
1186 @node Process Window Size
|
|
|
1187 @section Process Window Size
|
|
|
1188 @cindex process window size
|
|
|
1189
|
|
|
1190 @defun set-process-window-size process height width
|
|
|
1191 This function tells @var{process} that its logical window size is
|
|
|
1192 @var{height} by @var{width} characters. This is principally useful
|
|
|
1193 with pty's.
|
|
|
1194 @end defun
|
|
|
1195
|
|
|
1196 @node Transaction Queues
|
|
|
1197 @section Transaction Queues
|
|
|
1198 @cindex transaction queue
|
|
|
1199
|
|
|
1200 You can use a @dfn{transaction queue} for more convenient communication
|
|
|
1201 with subprocesses using transactions. First use @code{tq-create} to
|
|
|
1202 create a transaction queue communicating with a specified process. Then
|
|
|
1203 you can call @code{tq-enqueue} to send a transaction.
|
|
|
1204
|
|
|
1205 @defun tq-create process
|
|
|
1206 This function creates and returns a transaction queue communicating with
|
|
|
1207 @var{process}. The argument @var{process} should be a subprocess
|
|
|
1208 capable of sending and receiving streams of bytes. It may be a child
|
|
|
1209 process, or it may be a TCP connection to a server, possibly on another
|
|
|
1210 machine.
|
|
|
1211 @end defun
|
|
|
1212
|
|
|
1213 @defun tq-enqueue queue question regexp closure fn
|
|
|
1214 This function sends a transaction to queue @var{queue}. Specifying the
|
|
|
1215 queue has the effect of specifying the subprocess to talk to.
|
|
|
1216
|
|
|
1217 The argument @var{question} is the outgoing message that starts the
|
|
|
1218 transaction. The argument @var{fn} is the function to call when the
|
|
|
1219 corresponding answer comes back; it is called with two arguments:
|
|
|
1220 @var{closure}, and the answer received.
|
|
|
1221
|
|
|
1222 The argument @var{regexp} is a regular expression that should match the
|
|
|
1223 entire answer, but nothing less; that's how @code{tq-enqueue} determines
|
|
|
1224 where the answer ends.
|
|
|
1225
|
|
|
1226 The return value of @code{tq-enqueue} itself is not meaningful.
|
|
|
1227 @end defun
|
|
|
1228
|
|
|
1229 @defun tq-close queue
|
|
|
1230 Shut down transaction queue @var{queue}, waiting for all pending transactions
|
|
|
1231 to complete, and then terminate the connection or child process.
|
|
|
1232 @end defun
|
|
|
1233
|
|
|
1234 Transaction queues are implemented by means of a filter function.
|
|
|
1235 @xref{Filter Functions}.
|
|
|
1236
|
|
|
1237 @node Network
|
|
|
1238 @section Network Connections
|
|
|
1239 @cindex network connection
|
|
|
1240 @cindex TCP
|
|
|
1241
|
|
|
1242 XEmacs Lisp programs can open TCP network connections to other processes on
|
|
|
1243 the same machine or other machines. A network connection is handled by Lisp
|
|
|
1244 much like a subprocess, and is represented by a process object.
|
|
|
1245 However, the process you are communicating with is not a child of the
|
|
|
1246 XEmacs process, so you can't kill it or send it signals. All you can do
|
|
|
1247 is send and receive data. @code{delete-process} closes the connection,
|
|
|
1248 but does not kill the process at the other end; that process must decide
|
|
|
1249 what to do about closure of the connection.
|
|
|
1250
|
|
|
1251 You can distinguish process objects representing network connections
|
|
|
1252 from those representing subprocesses with the @code{process-status}
|
|
|
1253 function. It always returns either @code{open} or @code{closed} for a
|
|
|
1254 network connection, and it never returns either of those values for a
|
|
|
1255 real subprocess. @xref{Process Information}.
|
|
|
1256
|
|
|
1257 @defun open-network-stream name buffer-or-name host service
|
|
|
1258 This function opens a TCP connection for a service to a host. It
|
|
|
1259 returns a process object to represent the connection.
|
|
|
1260
|
|
|
1261 The @var{name} argument specifies the name for the process object. It
|
|
|
1262 is modified as necessary to make it unique.
|
|
|
1263
|
|
|
1264 The @var{buffer-or-name} argument is the buffer to associate with the
|
|
|
1265 connection. Output from the connection is inserted in the buffer,
|
|
|
1266 unless you specify a filter function to handle the output. If
|
|
|
1267 @var{buffer-or-name} is @code{nil}, it means that the connection is not
|
|
|
1268 associated with any buffer.
|
|
|
1269
|
|
|
1270 The arguments @var{host} and @var{service} specify where to connect to;
|
|
|
1271 @var{host} is the host name or IP address (a string), and @var{service}
|
|
|
1272 is the name of a defined network service (a string) or a port number (an
|
|
|
1273 integer).
|
|
|
1274 @end defun
|
