mktemp

MKTEMP(3)                  Linux Programmer's Manual                 MKTEMP(3)

NAME
       mktemp - make a unique temporary filename

SYNOPSIS
       #include <stdlib.h>

       char *mktemp(char *template);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mktemp():
           Since glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE ||
                   (_XOPEN_SOURCE >= 500 ||
                        _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
                   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
           Before glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
               _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION
       Never use this function; see BUGS.

       The mktemp() function generates a unique temporary filename  from  tem-
       plate.   The  last  six characters of template must be XXXXXX and these
       are replaced with a string that makes the filename  unique.   Since  it
       will be modified, template must not be a string constant, but should be
       declared as a character array.

RETURN VALUE
       The mktemp() function always returns template.  If a  unique  name  was
       created, the last six bytes of template will have been modified in such
       a way that the resulting name is unique (i.e., does not exist  already)
       If  a  unique  name  could  not  be  created, template is made an empty
       string, and errno is set to indicate the error.

ERRORS
       EINVAL The last six characters of template were not XXXXXX.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       +----------+---------------+---------+
       |Interface | Attribute     | Value   |
       +----------+---------------+---------+
       |mktemp()  | Thread safety | MT-Safe |
       +----------+---------------+---------+
CONFORMING TO
       4.3BSD,   POSIX.1-2001.   POSIX.1-2008  removes  the  specification  of
       mktemp().

BUGS
       Never use mktemp().  Some implementations  follow  4.3BSD  and  replace
       XXXXXX  by  the current process ID and a single letter, so that at most
       26 different names can be returned.  Since on the one  hand  the  names
       are  easy to guess, and on the other hand there is a race between test-
       ing whether the name exists and opening the file, every use of mktemp()
       is a security risk.  The race is avoided by mkstemp(3) and mkdtemp(3).

SEE ALSO
       mkdtemp(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)

COLOPHON
       This  page  is  part of release 4.04 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.

GNU                               2015-08-08                         MKTEMP(3)
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