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MKSTEMP(3P)                POSIX Programmer's Manual               MKSTEMP(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
       mkstemp - make a unique filename
SYNOPSIS
       #include <stdlib.h>
       int mkstemp(char *template);

DESCRIPTION
       The mkstemp() function shall replace the contents of the string pointed
       to  by  template by a unique filename, and return a file descriptor for
       the file open for reading and writing.  The function thus prevents  any
       possible  race  condition  between  testing whether the file exists and
       opening it for use. The string in template should look like a  filename
       with  six  trailing 'X' s; mkstemp() replaces each 'X' with a character
       from the portable filename character set.  The  characters  are  chosen
       such that the resulting name does not duplicate the name of an existing
       file at the time of a call to mkstemp().
RETURN VALUE
       Upon  successful  completion,  mkstemp()  shall  return  an  open  file
       descriptor.  Otherwise,  -1 shall be returned if no suitable file could
       be created.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
   Generating a Filename
       The following example creates a file with a 10-character name beginning
       with  the characters "file" and opens the file for reading and writing.
       The value returned as the value of fd is a file descriptor that identi-
       fies the file.

              #include <stdlib.h>
              ...
              char template[] = "/tmp/fileXXXXXX";
              int fd;

              fd = mkstemp(template);
APPLICATION USAGE
       It is possible to run out of letters.
       The mkstemp() function need not check to determine whether the filename
       part of template exceeds the maximum allowable filename length.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       getpid(), open(), tmpfile(), tmpnam(), the Base Definitions  volume  of
       IEEE Std 1003.1-2001, <stdlib.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  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 .

IEEE/The Open Group                  2003                          MKSTEMP(3P)