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 template. 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, and errno is set to indicate the error.
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 3.53 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
2013-04-19 MKTEMP(3)
