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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 (consult 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 existing 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  vol-
       ume 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 tmpnam() 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. Subse-
       quent calls to tmpnam() may modify the same object. If the  argument  s
       is  not a null pointer, it is presumed 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 responsi-
       bility 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,  Copyright  (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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                           TMPNAM(3P)