1MKSTEMP(P)                 POSIX Programmer's Manual                MKSTEMP(P)
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NAME

6       mkstemp - make a unique filename
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SYNOPSIS

9       #include <stdlib.h>
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11       int mkstemp(char *template);
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DESCRIPTION

15       The mkstemp() function shall replace the contents of the string pointed
16       to by template by a unique filename, and return a file  descriptor  for
17       the  file open for reading and writing.  The function thus prevents any
18       possible race condition between testing whether  the  file  exists  and
19       opening  it for use. The string in template should look like a filename
20       with six trailing 'X' s; mkstemp() replaces each 'X' with  a  character
21       from  the  portable  filename  character set. The characters are chosen
22       such that the resulting name does not duplicate the name of an existing
23       file at the time of a call to mkstemp().
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RETURN VALUE

26       Upon  successful  completion,  mkstemp()  shall  return  an  open  file
27       descriptor. Otherwise, -1 shall be returned if no suitable  file  could
28       be created.
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ERRORS

31       No errors are defined.
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33       The following sections are informative.
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EXAMPLES

36   Generating a Filename
37       The following example creates a file with a 10-character name beginning
38       with the characters "file" and opens the file for reading and  writing.
39       The value returned as the value of fd is a file descriptor that identi‐
40       fies the file.
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43              #include <stdlib.h>
44              ...
45              char template[] = "/tmp/fileXXXXXX";
46              int fd;
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49              fd = mkstemp(template);
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APPLICATION USAGE

52       It is possible to run out of letters.
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54       The mkstemp() function need not check to determine whether the filename
55       part of template exceeds the maximum allowable filename length.
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RATIONALE

58       None.
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FUTURE DIRECTIONS

61       None.
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SEE ALSO

64       getpid()  , open() , tmpfile() , tmpnam() , the Base Definitions volume
65       of IEEE Std 1003.1-2001, <stdlib.h>
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68       Portions of this text are reprinted and reproduced in  electronic  form
69       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
70       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
71       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
72       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
73       event of any discrepancy between this version and the original IEEE and
74       The Open Group Standard, the original IEEE and The Open Group  Standard
75       is  the  referee document. The original Standard can be obtained online
76       at http://www.opengroup.org/unix/online.html .
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80IEEE/The Open Group                  2003                           MKSTEMP(P)
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