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:
               (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L)
                   || /* Glibc since 2.19: */ _DEFAULT_SOURCE
                   || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
           Before glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500

DESCRIPTION
       Never use this function; see BUGS.

       The mktemp() function generates a unique temporary filename from
       template.  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
       testing 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
       mktemp(1), mkdtemp(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)

COLOPHON
       This page is part of release 5.05 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
       https://www.kernel.org/doc/man-pages/.



GNU                               2017-09-15                         MKTEMP(3)