mktemp - make a unique temporary filename
#include <stdlib.h> char *mktemp(char *template);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
- Since glibc 2.12:
(_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L) || /* Glibc since 2.19: */ _DEFAULT_SOURCE || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
- Before glibc 2.12:
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500
Never use this function; see BUGS.
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.
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.
The last six characters of
template were not XXXXXX.
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) and mkdtemp(3).
This page is part of release 5.10 of the Linux
man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.