mkdtemp — create a unique temporary directory


#include <stdlib.h>

char *mkdtemp(char *template);

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


/* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc 2.19 and earlier: */ _BSD_SOURCE
|| /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L


The mkdtemp() function generates a uniquely named temporary directory from template. The last six characters of template must be XXXXXX and these are replaced with a string that makes the directory name unique. The directory is then created with permissions 0700. Since it will be modified, template must not be a string constant, but should be declared as a character array.

Return Value

The mkdtemp() function returns a pointer to the modified template string on success, and NULL on failure, in which case errno is set appropriately.



The last six characters of template were not XXXXXX. Now template is unchanged.

Also see mkdir(2) for other possible values for errno.


Available since glibc 2.1.91.


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

Interface Attribute Value
mkdtemp() Thread safety MT-Safe

Conforming to

POSIX.1-2008. This function is present on the BSDs.

See Also

mktemp(1), mkdir(2), mkstemp(3), mktemp(3), tempnam(3), tmpfile(3), tmpnam(3)


This page is part of release 5.04 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

Referenced By

file-hierarchy(7), guestfish(1), guestfs(3), i3(1), mkstemp(3), mktemp(1), mktemp(3).

2016-07-17 GNU Linux Programmer's Manual