redhat man page for mktemp

MKTEMP(3)						     Linux Programmer's Manual							 MKTEMP(3)

NAME
       mktemp - make a unique temporary file name

SYNOPSIS
       #include <stdlib.h>

       char *mktemp(char *template);

DESCRIPTION
       The  mktemp()  function generates a unique temporary file name 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 returns NULL on error (template did not end in XXXXXX) and template otherwise.  If the call was successful, the last
       six bytes of template will have been modified in such a way that the resulting name is unique (does not exist already).	If  the  call  was
       unsuccessful, template is made an empty string.

ERRORS
       EINVAL The last six characters of template were not XXXXXX.

CONFORMING TO
       BSD 4.3. POSIX dictates tmpnam(3).

NOTE
       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 BSD 4.3 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)

GNU
								    1993-04-03								 MKTEMP(3)