TMPNAM(3P)                                          POSIX Programmer's Manual                                         TMPNAM(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       tmpnam - create a name for a temporary file

SYNOPSIS
       #include <stdio.h>

       char *tmpnam(char *s);


DESCRIPTION
       The  tmpnam() function shall generate a string that is a valid filename and that is not the same as the name of an exist-
       ing file. The function is potentially capable of generating {TMP_MAX} different strings, but  any  or  all  of  them  may
       already be in use by existing files and thus not be suitable return values.

       The  tmpnam()  function generates a different string each time it is called from the same process, up to {TMP_MAX} times.
       If it is called more than {TMP_MAX} times, the behavior is implementation-defined.

       The implementation shall behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls tmpnam().

       If the application uses any of the functions  guaranteed  to  be  available  if  either  _POSIX_THREAD_SAFE_FUNCTIONS  or
       _POSIX_THREADS is defined, the application shall ensure that the tmpnam() function is called with a non-NULL parameter.

RETURN VALUE
       Upon successful completion, tmpnam() shall return a pointer to a string. If no suitable string can be generated, the tmp-
       nam() function shall return a null pointer.

       If the argument s is a null pointer, tmpnam() shall leave its result in an internal static object and return a pointer to
       that object. Subsequent calls to tmpnam() may modify the same object. If the argument s is not a null pointer, it is pre-
       sumed to point to an array of at least L_tmpnam chars; tmpnam() shall write its result in that array and shall return the
       argument as its value.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
   Generating a Filename
       The following example generates a unique filename and stores it in the array pointed to by ptr.


              #include <stdio.h>
              ...
              char filename[L_tmpnam+1];
              char *ptr;


              ptr = tmpnam(filename);

APPLICATION USAGE
       This function only creates filenames. It is the application's responsibility to create and remove the files.

       Between  the  time  a  pathname is created and the file is opened, it is possible for some other process to create a file
       with the same name. Applications may find tmpfile() more useful.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       fopen(), open(), tempnam(), tmpfile(), unlink(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    TMPNAM(3P)