Copyright (c) 1989 The Regents of the University of California.
All rights reserved.

%sccs.include.redist.man%

@(#)mktemp.3 6.8 (Berkeley) 03/05/91

.AT 3 mktemp - create a unique file name

#include <unistd.h>

char *mktemp(char *template);

int mkstemp(char *template);

Mktemp takes a file name template and overwrites it to create a unique file name for use by the application. The template may be any file name with some number of X's appended to it, for example ``/tmp/temp.XXXX''. The trailing X's 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 X's provided; six X's will result in mktemp testing roughly 26 ** 6 combinations.

Mkstemp 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.

Mktemp returns a pointer to the template on success and NULL on failure. Mkstemp returns -1 if no suitable file could be created. If either call fails an error code is placed in the global location errno . Mktemp and mkstemp may set errno to one of the following values:

[ENOTDIR] The pathname portion of the template is not an existing directory.

Mktemp and mkstemp may also set errno to any value specified by the stat (2) function. Mkstemp may also set errno to any value specified by the open (2) function.

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