MKTEMP(3) MachTen Programmer’s Manual MKTEMP(3)

NAME
mktemp - make temporary file name (unique)

SYNOPSIS
#include <unistd.h>

char *
mktemp(char *template)

int
mkstemp(char *template)

DESCRIPTION
The mktemp() function takes the given file name template and overwrites a
portion of it to create a file name. This file name is unique and suit-
able for use by the application. The template may be any file name with
some number of ‘Xs’ appended to it, for example /tmp/temp.XXXX. The
trailing ‘Xs’ are replaced with the current process number and/or a
unique letter combination. The number of unique file names mktemp() can
return depends on the number of ‘Xs’ provided; six ‘Xs’ will result in
mktemp() testing roughly 26 ** 6 combinations.

The mkstemp() function makes the same replacement to the template and
creates the template file, mode 0600, returning a file descriptor opened
for reading and writing. This avoids the race between testing for a
file’s existence and opening it for use.

RETURN VALUES
The mktemp() function returns a pointer to the template on success and
NULL on failure. The mkstemp() function returns -1 if no suitable file
could be created. If either call fails an error code is placed in the
global variable errno.

ERRORS
The mktemp() and mkstemp() functions may set errno to one of the follow-
ing values:

[ENOTDIR] The pathname portion of the template is not an existing direc-
tory.

The mktemp() and mkstemp() functions may also set errno to any value
specified by the stat(2) function.

The mkstemp() function may also set errno to any value specified by the
open(2) function.

SEE ALSO
chmod(2), getpid(2), open(2), stat(2)

HISTORY
A mktemp function appeared in Version 7 AT&T UNIX.

4.4BSD June 4, 1993 1