MKTEMP (3)
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().
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 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
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