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MKTEMP(3)		     Library Functions Manual		       MKTEMP(3)

NAME
     mktemp, mkstemp, mkdtemp -- make unique temporary file or directory name

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <stdlib.h>

     char *
     mktemp(char *template);

     int
     mkstemp(char *template);

     char *
     mkdtemp(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 suitable
     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 cre-
     ates the template file, mode 0600, returning a file descriptor  opened  for
     reading and writing.  This avoids the race between testing for a file's ex-
     istence and opening it for use.

     The  mkdtemp() function is similar to mkstemp(), but it creates a mode 0700
     directory instead and returns the path.

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

ERRORS
     The mktemp(), mkstemp() and mkdtemp() functions may set errno to one of the
     following values:

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

     The  mktemp(),  mkstemp() and mkdtemp() 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.

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

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

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

     The mkstemp() function appeared in 4.4BSD.

     The mkdtemp() function appeared in NetBSD 1.4.

SECURITY CONSIDERATIONS
     The use of mktemp() should generally be avoided, as a hostile  process  can
     exploit  a race condition in the time between the generation of a temporary
     filename by mktemp() and the invoker's use of the temporary name.	A  link-
     time  warning will be issued advising the use of mkstemp() or mkdtemp() in-
     stead.

NetBSD 1.4			  July 28, 1998 		       MKTEMP(3)
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