tmpnam(3p) — Linux manual page

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 functionality described on this reference page is aligned
       with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This
       volume of POSIX.1‐2017 defers to the ISO C standard.

       The tmpnam() function shall generate a string that is a valid
       pathname that does not name 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
       volume of POSIX.1‐2017, except tempnam(), calls tmpnam().

       The tmpnam() function need not be thread-safe if called with a
       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. Subsequent 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 Pathname
       The following example generates a unique pathname and stores it
       in the array pointed to by ptr.

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

           ptr = tmpnam(pathname);

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.

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

RATIONALE

       None.

FUTURE DIRECTIONS

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

SEE ALSO

       fopen(3p), open(3p), mkdtemp(3p), tempnam(3p), tmpfile(3p),
       unlink(3p)

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

COPYRIGHT

       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                        TMPNAM(3P)

Pages that refer to this page: stdio.h(0p), mkdtemp(3p), tempnam(3p), tmpfile(3p)

---