1TMPFILE(3P)                POSIX Programmer's Manual               TMPFILE(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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11

NAME

13       tmpfile — create a temporary file
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SYNOPSIS

16       #include <stdio.h>
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18       FILE *tmpfile(void);
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DESCRIPTION

21       The functionality described on this reference page is aligned with  the
22       ISO C  standard.  Any  conflict between the requirements described here
23       and the ISO C standard is unintentional. This  volume  of  POSIX.1‐2008
24       defers to the ISO C standard.
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26       The  tmpfile() function shall create a temporary file and open a corre‐
27       sponding stream. The file shall be automatically deleted when all  ref‐
28       erences  to  the  file are closed. The file is opened as in fopen() for
29       update (w+), except that implementations may restrict the  permissions,
30       either  by  clearing  the  file  mode bits or setting them to the value
31       S_IRUSR | S_IWUSR.
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33       In some implementations, a permanent file may be  left  behind  if  the
34       process  calling  tmpfile()  is killed while it is processing a call to
35       tmpfile().
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37       An error message may be written to standard error if the stream  cannot
38       be opened.
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RETURN VALUE

41       Upon  successful  completion,  tmpfile()  shall return a pointer to the
42       stream of the file that is created.  Otherwise, it shall return a  null
43       pointer and set errno to indicate the error.
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ERRORS

46       The tmpfile() function shall fail if:
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48       EINTR  A signal was caught during tmpfile().
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50       EMFILE All  file  descriptors  available  to  the process are currently
51              open.
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53       EMFILE {STREAM_MAX} streams are currently open in the calling process.
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55       ENFILE The maximum allowable number of files is currently open  in  the
56              system.
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58       ENOSPC The  directory  or  file system which would contain the new file
59              cannot be expanded.
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61       EOVERFLOW
62              The file is a regular file and the size of the  file  cannot  be
63              represented correctly in an object of type off_t.
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65       The tmpfile() function may fail if:
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67       EMFILE {FOPEN_MAX} streams are currently open in the calling process.
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69       ENOMEM Insufficient storage space is available.
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71       The following sections are informative.
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EXAMPLES

74   Creating a Temporary File
75       The  following example creates a temporary file for update, and returns
76       a pointer to a stream for the created file in the fp variable.
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78           #include <stdio.h>
79           ...
80           FILE *fp;
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82           fp = tmpfile ();
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APPLICATION USAGE

85       It should be possible to open at least {TMP_MAX} temporary files during
86       the  lifetime  of  the program (this limit may be shared with tmpnam())
87       and there should be no limit on the number  simultaneously  open  other
88       than this limit and any limit on the number of open file descriptors or
89       streams ({OPEN_MAX}, {FOPEN_MAX}, {STREAM_MAX}).
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RATIONALE

92       None.
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FUTURE DIRECTIONS

95       None.
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SEE ALSO

98       Section  2.5,  Standard  I/O  Streams,  fopen(),  mkdtemp(),  tmpnam(),
99       unlink()
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101       The Base Definitions volume of POSIX.1‐2008, <stdio.h>
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104       Portions  of  this text are reprinted and reproduced in electronic form
105       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
106       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
107       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
108       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
109       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
110       event of any discrepancy between this version and the original IEEE and
111       The Open Group Standard, the original IEEE and The Open Group  Standard
112       is  the  referee document. The original Standard can be obtained online
113       at http://www.unix.org/online.html .
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115       Any typographical or formatting errors that appear  in  this  page  are
116       most likely to have been introduced during the conversion of the source
117       files to man page format. To report such errors,  see  https://www.ker‐
118       nel.org/doc/man-pages/reporting_bugs.html .
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122IEEE/The Open Group                  2013                          TMPFILE(3P)
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