MKDTEMP(3)                 POSIX Programmer's Manual                MKDTEMP(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.


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 ''XX''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 ''XX''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 aa 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 .



IEEE/The Open Group                  2013                           MKDTEMP(3)
