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MKDTEMP(3P)                POSIX Programmer's Manual               MKDTEMP(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
       mkdtemp, mkstemp -- create a unique directory or file
SYNOPSIS
       #include <stdlib.h>
       char *mkdtemp(char *template);
       int mkstemp(char *template);
DESCRIPTION
       The mkdtemp() function uses the contents of  template  to  construct  a
       unique directory name. The string provided in template shall be a path-
       name ending with six  trailing  'X's.   The  mkdtemp()  function  shall
       replace  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
       mkdtemp().  The unique directory name is used to attempt to create  the
       directory using mode 0700 as modified by the file creation mask.
       The mkstemp() function shall replace the contents of the string pointed
       to by template by a unique pathname, and return a file  descriptor  for
       the  file  open  for  reading and writing. The mkstemp() function shall
       create the file, and obtain a file descriptor for it, as if by  a  call
       to:
           open(pathname, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR)
       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 pathname 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,  the  mkdtemp()  function  shall  return  a
       pointer  to the string containing the directory name if it was created.
       Otherwise, it shall return a null pointer and shall set errno to  indi-
       cate the error.
       Upon successful completion, the mkstemp() function shall return an open
       file descriptor. Otherwise, it shall return  -1  if  no  suitable  file
       could be created.
ERRORS
       The mkdtemp() function shall fail if:
       EACCES Search  permission  is denied on a component of the path prefix,
              or write permission is denied on the  parent  directory  of  the
              directory to be created.
       EINVAL The string pointed to by template does not end in "XXXXXX".
       ELOOP  A loop exists in symbolic links encountered during resolution of
              the path of the directory to be created.
       EMLINK The link count of the parent directory would exceed {LINK_MAX}.
       ENAMETOOLONG
              The  length  of  a  component  of  a  pathname  is  longer  than
              {NAME_MAX}.
       ENOENT A  component  of the path prefix specified by the template argu-
              ment does not name an existing directory.
       ENOSPC The file system does not contain enough space to hold  the  con-
              tents  of the new directory or to extend the parent directory of
              the new directory.
       ENOTDIR
              A component of the path prefix names an existing  file  that  is
              neither a directory nor a symbolic link to a directory.
       EROFS  The parent directory resides on a read-only file system.
       The mkdtemp() function may fail if:
       ELOOP  More  than  {SYMLOOP_MAX} symbolic links were encountered during
              resolution of the path of the directory to be created.
       ENAMETOOLONG
              The length of a pathname exceeds {PATH_MAX}, or pathname resolu-
              tion  of  a symbolic link produced an intermediate result with a
              length that exceeds {PATH_MAX}.
       The error conditions for the mkstemp() function are defined in open().
       The following sections are informative.
EXAMPLES
   Generating a Pathname
       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  mkdtemp()  and  mkstemp()  functions  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(), mkdir(), open(), tmpfile(), tmpnam()
       The Base Definitions volume of POSIX.1-2008, <stdlib.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 Electri-
       cal  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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                          MKDTEMP(3P)