mktemp(3) — Linux manual page


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

NAME         top

       mktemp - make a unique temporary filename

SYNOPSIS         top

       #include <stdlib.h>

       char *mktemp(char *template);

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

           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         top

       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         top

       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         top

       EINVAL The last six characters of template were not XXXXXX.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface Attribute     Value   │
       │mktemp()  │ Thread safety │ MT-Safe │

CONFORMING TO         top

       4.3BSD, POSIX.1-2001.  POSIX.1-2008 removes the specification of

BUGS         top

       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

SEE ALSO         top

       mktemp(1), mkdtemp(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)

COLOPHON         top

       This page is part of release 5.08 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

GNU                              2017-09-15                        MKTEMP(3)

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