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

PROLOG         top

       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         top

       tempnam — create a name for a temporary file

SYNOPSIS         top

       #include <stdio.h>

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

DESCRIPTION         top

       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

       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         top

       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         top

       The tempnam() function shall fail if:

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES         top

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

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

           file = tempnam(directory, fileprefix);


       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.

       Applications should use the tmpfile(), mkdtemp(), or mkstemp()
       functions instead of the obsolescent tempnam() function.

RATIONALE         top



       The tempnam() function may be removed in a future version.

SEE ALSO         top

       fopen(3p), free(3p), mkdtemp(3p), open(3p), tmpfile(3p), tmpnam(3p),

       The Base Definitions volume of POSIX.1‐2008, stdio.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                         TEMPNAM(3P)