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 .

       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.kernel.org/doc/man-pages/reporting_bugs.html .