MKTEMP(3) Linux Programmer's Manual MKTEMP(3)
NAME
mktemp - make a unique temporary filename
SYNOPSIS
#include <stdlib.h>
char *mktemp(char *template);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
mktemp():
Since glibc 2.12:
_BSD_SOURCE || _SVID_SOURCE ||
(_XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
!(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
Before glibc 2.12:
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
DESCRIPTION
The mktemp() function generates a unique temporary filename from tem-
plate. The last six characters of template must be XXXXXX and these
are replaced with a string that makes the filename unique. Since it
will be modified, template must not be a string constant, but should be
declared as a character array.
RETURN VALUE
The mktemp() function always returns template. If a unique name was
created, the last six bytes of template will have been modified in such
a way that the resulting name is unique (i.e., does not exist already)
If a unique name could not be created, template is made an empty
string.
ERRORS
EINVAL The last six characters of template were not XXXXXX.
CONFORMING TO
4.3BSD, POSIX.1-2001. POSIX.1-2008 removes the specification of
mktemp().
NOTES
The prototype is in <unistd.h> for libc4, libc5, glibc1; glibc2 follows
the Single Unix Specification and has the prototype in <stdlib.h>.
BUGS
Never use mktemp(). Some implementations follow 4.3BSD and replace
XXXXXX by the current process ID and a single letter, so that at most
26 different names can be returned. Since on the one hand the names
are easy to guess, and on the other hand there is a race between test-
ing whether the name exists and opening the file, every use of mktemp()
is a security risk. The race is avoided by mkstemp(3).
SEE ALSO
mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)
COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2010-09-20 MKTEMP(3)
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