tmpfile
create a temporary file
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SYNOPSIS
#include <stdio.h>
FILE *tmpfile(void);
DESCRIPTION
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 is opened as in fopen() for update (w+).
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
- {OPEN_MAX} file descriptors 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 files ( {FOPEN_MAX}).
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fopen() , tmpnam() , unlink() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .