tmpfile(3p) — Linux manual page

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

       tmpfile — create a temporary file

SYNOPSIS

       #include <stdio.h>

       FILE *tmpfile(void);

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 tmpfile() function shall create a temporary file and open a
       corresponding stream. The file shall be automatically deleted
       when all references to the file are closed. The file shall be
       opened as in fopen() for update (wb+), except that
       implementations may restrict the permissions, either by clearing
       the file mode bits or setting them to the value S_IRUSR |
       S_IWUSR.

       In some implementations, a permanent file may be left behind if
       the process calling tmpfile() is killed while it is processing a
       call to tmpfile().

       An error message may be written to standard error if the stream
       cannot be opened.

RETURN VALUE

       Upon successful completion, tmpfile() shall return a pointer to
       the stream of the file that is created.  Otherwise, it shall
       return a null pointer and set errno to indicate the error.

ERRORS

       The tmpfile() function shall fail if:

       EINTR  A signal was caught during tmpfile().

       EMFILE All file descriptors available to the process are
              currently open.

       EMFILE {STREAM_MAX} streams are currently open in the calling
              process.

       ENFILE The maximum allowable number of files is currently open in
              the system.

       ENOSPC The directory or file system which would contain the new
              file cannot be expanded.

       EOVERFLOW
              The file is a regular file and the size of the file cannot
              be represented correctly in an object of type off_t.

       The tmpfile() function may fail if:

       EMFILE {FOPEN_MAX} streams are currently open in the calling
              process.

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES

   Creating a Temporary File
       The following example creates a temporary file for update, and
       returns a pointer to a stream for the created file in the fp
       variable.

           #include <stdio.h>
           ...
           FILE *fp;

           fp = tmpfile ();

APPLICATION USAGE

       It should be possible to open at least {TMP_MAX} temporary files
       during the lifetime of the program (this limit may be shared with
       tmpnam()) and there should be no limit on the number
       simultaneously open other than this limit and any limit on the
       number of open file descriptors or streams ({OPEN_MAX},
       {FOPEN_MAX}, {STREAM_MAX}).

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Section 2.5, Standard I/O Streams, fopen(3p), mkdtemp(3p),
       tmpnam(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                       TMPFILE(3P)

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

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