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.
NAMEtmpfile — 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.1‐2008
defers to the ISO C standard.
The tmpfile() function shall create a temporary file and open a corre‐
sponding stream. The file shall be automatically deleted when all ref‐
erences to the file are closed. The file is opened as in fopen() for
update (w+), 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(), mkdtemp(), tmpnam(),
unlink()
The Base Definitions volume of POSIX.1‐2008, <stdio.h>
COPYRIGHT
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 Electri‐
cal 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 http://www.unix.org/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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 TMPFILE(3P)
