mktemp - make a unique temporary file name
char *mktemp(char *template);
The mktemp() function generates a unique temporary file name 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.
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.
EINVAL The last six characters of template were not XXXXXX.
BSD 4.3. POSIX dictates tmpnam(3).
The prototype is in <unistd.h> for libc4, libc5, glibc1; glibc2 follows
the Single Unix Specification and has the prototype in <stdlib.h>.
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 testing
whether the name exists and opening the file, every use of mktemp()
is a security risk. The race is avoided by mkstemp(3).
mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)
GNU 1993-04-03 MKTEMP(3)
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