tmpfile(3C) Standard C Library Functions tmpfile(3C)NAME
tmpfile - create a temporary file
SYNOPSIS
#include <stdio.h>
FILE *tmpfile(void);
DESCRIPTION
The tmpfile() function creates a temporary file and opens a corresponding stream. The file will automatically be deleted when all refer-
ences to the file are closed. The file is opened as in fopen(3C) for update (w+).
The largest value that can be represented correctly in an object of type off_t will be established as the offset maximum in the open file
description.
RETURN VALUES
Upon successful completion, tmpfile() returns a pointer to the stream of the file that is created. Otherwise, it returns a null pointer and
sets errno to indicate the error.
ERRORS
The tmpfile() function will fail if:
EINTR A signal was caught during the execution of tmpfile().
EMFILE There are OPEN_MAX file descriptors 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.
The tmpfile() function may fail if:
EMFILE There are FOPEN_MAX streams currently open in the calling process.
ENOMEM Insufficient storage space is available.
USAGE
The stream refers to a file which is unlinked. If the process is killed in the period between file creation and unlinking, a permanent
file may be left behind.
The tmpfile() function has a transitional interface for 64-bit file offsets. See lf64(5).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO unlink(2), fopen(3C), mkstemp(3C), mktemp(3C), tmpnam(3C), lf64(5), standards(5)SunOS 5.11 4 Aug 2003 tmpfile(3C)
Check Out this Related Man 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 correspond-
ing 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.1-2008 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 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 tmp-
nam()) 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 Technol-
ogy -- 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 Stan-
dard 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.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE /The Open Group 2013 TMPFILE(3P)