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comparison src/dlopen.c @ 245:51092a27c943 r20-5b21

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Import from CVS: tag r20-5b21
author cvs
date Mon, 13 Aug 2007 10:17:54 +0200
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244:78d4f1140794 245:51092a27c943
1 /* Lisp interface to dynamic loading.
2 Copyright (C) 1998 Joshua Rowe.
3 Additional cleanup by Hrvoje Niksic.
4
5 This file is part of XEmacs.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; see the file COPYING. If not, write to
19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 /* Synched up with: Not in FSF. */
23
24 /* A shared object may have the following symbols defined:
25 syms_of
26 vars_of
27 complex_vars_of
28 They are called in that order. Each takes and returns void
29 arguments.
30
31 All of this needs lots and LOTS of work. Some things to work on:
32
33 1) A good foreign interface. We probably need to get rid of
34 syms_of and similar junk, and define a more normal interfacing to
35 the outside world, e.g. an init_emacs_module() function. See below
36 for more discussion about it. Also, we need a modules/ directory
37 with a few nice sample modules, a sample Makefile, etc. so people
38 can start hacking.
39
40 2) Compatibility concerns. There are systems without dynamic
41 libraries (Ultrix, to name one). OK, scrap them, but not all
42 systems out there use the exact dlopen() interface that this file
43 uses. Bill Perry said he had ready Makefiles for 14 or so systems
44 to do this sort of things portably. Check it out. Or, use Gordon
45 Matzigkeit's libtool.
46
47 3) I'm getting coredumps very often -- practically every time I
48 compile without USE_MINIMAL_TAGBITS, and even with it sometimes. I
49 wasn't able to resolve these.
50
51 4) All of this is sooo simple-minded. As it gets more complex,
52 we'll have to look at how others have done similar things
53 (e.g. Perl and Zsh 3.1), to avoid botching it up. */
54
55 #include <config.h>
56 #include "lisp.h"
57 #include "emacsfns.h"
58 #include "buffer.h"
59
60 #include <stdio.h>
61 #include <dlfcn.h>
62 #include <errno.h>
63
64
65 DEFUN ("dl-open", Fdl_open, 1, 1, "FShared object: ", /*
66 Load LIBRARY as a shared object file.
67
68 After the LIBRARY is dynamically linked with the executable, the
69 following functions are called:
70
71 syms_of(), containing definitions of symbols and subr's;
72 vars_of(), containing definitions of variables;
73 complex_vars_of(), containing complex definitions of variables.
74
75 After this point, any lisp symbols defined in the shared object are
76 available for use.
77 */
78 (library))
79 {
80 /* This function can GC */
81 void *handle;
82 char *file;
83 void (*function)();
84
85 CHECK_STRING (library);
86 library = Fexpand_file_name (library, Qnil);
87
88 file = XSTRING_DATA (library);
89 /* #### Is this right? */
90 GET_C_CHARPTR_EXT_FILENAME_DATA_ALLOCA (file, file);
91
92 handle = dlopen (file, RTLD_LAZY);
93 if (handle == NULL)
94 {
95 signal_error (Qerror,
96 list3 (build_translated_string ("Cannot load shared library"),
97 library, build_translated_string (dlerror ())));
98 }
99
100 /* #### This looks unnecessary here, because at this time one
101 initialization function is fully sufficient. However, I am not
102 removing this support, since we may wish to add mechanisms for
103 static linking, which would have invoke these function via normal
104 paths.
105
106 #### But then this is not sufficient, because one could as well
107 honor specifier_vars_of_foo(), etc. Maybe we should scrap it
108 after all.
109
110 #### What if one of the first two functions signal an error?
111 Should we take care to execute the other two? My fingers are
112 getting itchy! */
113
114 function = dlsym (handle, "syms_of");
115 if (function)
116 {
117 function ();
118 }
119
120 function = dlsym (handle, "vars_of");
121 if (function)
122 {
123 function ();
124 }
125
126 function = dlsym (handle, "complex_vars_of");
127 if (function)
128 {
129 function ();
130 }
131
132 return Qnil;
133 }
134
135 void syms_of_dlopen ()
136 {
137 DEFSUBR (Fdl_open);
138 }