tempnam(3p) — Linux manual page


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 pathname.

           #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), unlink(3p)

       The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       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
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                       TEMPNAM(3P)

Pages that refer to this page: stdio.h(0p)tmpnam(3p)