ultrix man page for tmpnam

tmpnam(3s)																tmpnam(3s)

Name
       tmpnam, tempnam - create a name for a temporary file

Syntax
       #include <stdio.h>

       char *tmpnam (s)
       char *s;

       char *tempnam (dir, pfx)
       char *dir, *pfx;

Description
       These functions generate file names that can safely be used for a temporary file.

       The  subroutine	always generates a file name using the path-name defined as in the <stdio.h> header file.  If s is NULL, leaves its result
       in an internal static area and returns a pointer to that area.  The next call to will destroy the contents of the area.	If s is not  NULL,
       it  is  assumed	to be the address of an array of at least bytes, where is a constant defined in <stdio.h>; places its result in that array
       and returns s.

       The subroutine allows the user to control the choice of a directory.  The argument dir points to the path-name of the  directory  in  which
       the  file  is  to  be  created.	 If dir is NULL or points to a string which is not a path-name for an appropriate directory, the path-name
       defined as in the <stdio.h> header file is used.  If that path-name is not accessible, will be used as a last resort.  This entire sequence
       can  be	up-staged by providing an environment variable TMPDIR in the user's environment, whose value is a path-name for the desired tempo-
       rary-file directory.

       Many applications prefer their temporary files to have certain favorite initial letter sequences in their names.  Use the pfx argument  for
       this.  This argument may be NULL or point to a string of up to five characters to be used as the first few characters of the temporary-file
       name.

       The subroutine uses to get space for the constructed file name, and returns a pointer to this area.  Thus, any pointer value returned  from
       may  serve  as  an  argument to free.  For further information, see If cannot return the expected result for any reason, that is failed, or
       none of the above mentioned attempts to find an appropriate directory was successful, a NULL pointer will be returned.	The  and  routines
       generate a different file name each time they are called.

       Files  created  using  these functions and either or are temporary only in the sense that they reside in a directory intended for temporary
       use, and their names are unique.  It is the user's responsibility to use to remove the file when its use is ended.

Restrictions
       If called more than 17,576 times in a single process, these functions will start recycling previously used names.

       Between the time a file name is created and the file is opened, it is possible for some other process to create a file with the same  name.
       This  can never happen if that other process is using these functions or and the file names are chosen so as to render duplication by other
       means unlikely.

See Also
       creat(2), unlink(2), fopen(3s), malloc(3), mktemp(3), tmpfile(3s)

																	tmpnam(3s)