PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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         top

       mkdtemp, mkstemp — create a unique directory or file

SYNOPSIS         top

       #include <stdlib.h>

       char *mkdtemp(char *template);
       int mkstemp(char *template);

DESCRIPTION         top

       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         top

       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         top

       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(3p).

       The following sections are informative.

EXAMPLES         top

   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         top

       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         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       getpid(3p), mkdir(3p), open(3p), tmpfile(3p), tmpnam(3p)

       The Base Definitions volume of POSIX.1‐2008, stdlib.h(0p)

COPYRIGHT         top

       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(3P)