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comparison man/lispref/files.texi @ 290:c9fe270a4101 r21-0b43

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Import from CVS: tag r21-0b43
author cvs
date Mon, 13 Aug 2007 10:36:47 +0200
parents 7df0dd720c89
children 6240c7796c7a
comparison
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289:6e6992ccc4b6 290:c9fe270a4101
1631 1631
1632 Some programs need to write temporary files. Here is the usual way to 1632 Some programs need to write temporary files. Here is the usual way to
1633 construct a name for such a file: 1633 construct a name for such a file:
1634 1634
1635 @example 1635 @example
1636 (make-temp-name (concat "/tmp/" @var{name-of-application})) 1636 (make-temp-name (expand-file-name @var{name-of-application} (temp-directory)))
1637 @end example 1637 @end example
1638 1638
1639 @noindent 1639 @noindent
1640 Here we use the directory @file{/tmp/} because that is the standard 1640 Here we use @code{(temp-directory)} to specify a directory for temporary
1641 place on Unix for temporary files. The job of @code{make-temp-name} is 1641 files---under Unix, it will normally evaluate to @file{"/tmp/"}. The
1642 to prevent two different users or two different processes from trying to 1642 job of @code{make-temp-name} is to prevent two different users or two
1643 use the same name. 1643 different processes from trying to use the same name.
1644 1644
1645 @defun make-temp-name string 1645 @defun temp-directory
1646 This function generates a string that can be used as a unique name. The 1646 This function returns the name of the directory to use for temporary
1647 name starts with @var{string}, and ends with a number that is different 1647 files. Under Unix, this will be the value of @code{TMPDIR}, defaulting
1648 in each XEmacs process. 1648 to @file{/tmp}. On Windows, this will be obtained from the @code{TEMP}
1649 or @code{TMP} environment variables, defaulting to @file{/}.
1650
1651 Note that the @code{temp-directory} function does not exist under FSF
1652 Emacs.
1653 @end defun
1654
1655 @defun make-temp-name prefix
1656 This function generates a temporary file name starting with
1657 @var{prefix}. The Emacs process number forms part of the result, so
1658 there is no danger of generating a name being used by another process.
1649 1659
1650 @example 1660 @example
1651 @group 1661 @group
1652 (make-temp-name "/tmp/foo") 1662 (make-temp-name "/tmp/foo")
1653 @result{} "/tmp/foo021304" 1663 @result{} "/tmp/fooGaAQjC"
1654 @end group 1664 @end group
1655 @end example 1665 @end example
1656 1666
1657 To prevent conflicts among different libraries running in the same 1667 In addition, this function makes an attempt to choose a name that does
1658 XEmacs, each Lisp program that uses @code{make-temp-name} should have its 1668 not specify an existing file. To make this work, @var{prefix} should be
1659 own @var{string}. The number added to the end of the name distinguishes 1669 an absolute file name.
1660 between the same application running in different XEmacs processes. 1670
1671 To avoid confusion, each Lisp application should preferably use a unique
1672 @var{prefix} to @code{make-temp-name}.
1661 @end defun 1673 @end defun
1662 1674
1663 @node File Name Completion 1675 @node File Name Completion
1664 @subsection File Name Completion 1676 @subsection File Name Completion
1665 @cindex file name completion subroutines 1677 @cindex file name completion subroutines