huschi.net

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.1-2008
       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)