TEMPNAM(3P)                                         POSIX Programmer's Manual                                        TEMPNAM(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
       tempnam - create a name for a temporary file

SYNOPSIS
       #include <stdio.h>

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


DESCRIPTION
       The tempnam() function shall generate a pathname that may be used for a temporary file.

       The  tempnam()  function allows the user to control the choice of a directory. The dir argument points to the name of the
       directory in which the file is to be created. If dir is a null pointer or points to a string which is not a name  for  an
       appropriate  directory,  the  path prefix defined as P_tmpdir in the <stdio.h> header shall be used. If that directory is
       not accessible, an implementation-defined directory may be used.

       Many applications prefer their temporary files to have certain initial letter sequences in their names. The pfx  argument
       should  be  used for this. This argument may be a null pointer or point to a string of up to five bytes to be used as the
       beginning of the filename.

       Some implementations of tempnam() may use tmpnam() internally.  On such implementations, if called  more  than  {TMP_MAX}
       times in a single process, the behavior is implementation-defined.

RETURN VALUE
       Upon  successful  completion,  tempnam() shall allocate space for a string, put the generated pathname in that space, and
       return a pointer to it. The pointer shall be suitable for use in a subsequent call to free(). Otherwise, it shall  return
       a null pointer and set errno to indicate the error.

ERRORS
       The tempnam() function shall fail if:

       ENOMEM Insufficient storage space is available.


       The following sections are informative.

EXAMPLES
   Generating a Pathname
       The  following example generates a pathname for a temporary file in directory /tmp, with the prefix file. After the file-
       name has been created, the call to free() deallocates the space used to store the filename.


              #include <stdio.h>
              #include <stdlib.h>
              ...
              char *directory = "/tmp";
              char *fileprefix = "file";
              char *file;


              file = tempnam(directory, fileprefix);
              free(file);

APPLICATION USAGE
       This function only creates pathnames. 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(), free(), open(), tmpfile(), tmpnam(), 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                                                   TEMPNAM(3P)