table of contents
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 testing 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¶
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/.
2013-04-19 | GNU |