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 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+), 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 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 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.kernel.org/doc/man-pages/reporting_bugs.html .