oracular (3) tmpfile.3posix.gz

Provided by: manpages-posix-dev_2017a-2_all bug

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.1‐2017 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 shall be opened as in  fopen()
       for  update  (wb+), 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.1‐2017, <stdio.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       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 .