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 pathname 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
       indicate 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 argument does not name an existing
              directory.

       ENOSPC The file system does not contain enough space to hold the contents 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 resolution 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
       identifies 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 Electrical 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 .

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       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 .