MKTEMP(3) Library Functions Manual MKTEMP(3)NAME
mktemp - make a unique file name
Mktemp creates a unique file name and returns the address of the template. The template should contain a file name with trailing X's, nor-
mally something like /tmp/tempXXXXXX. The X's are replaced by the current process number and/or a unique letter combination. Mkstemp
makes the same replacement to the template but opens the template file and returns a file descriptor open for reading and writing. Mkstemp
avoids the race between testing whether the file exists and opening it for use. The number of file name combinations mktemp and mkstemp
will try depends on the number of X's placed on the end of the template; six X's will result in them trying roughly 26 ** 6 combinations.
SEE ALSO access(2), getpid(2), open(2)DIAGNOSTICS
Mktemp returns NULL on failure, mkstemp returns -1 if no suitable file could be created.
7th Edition April 10, 1987 MKTEMP(3)
Check Out this Related Man Page
MKTEMP(3) Linux Programmer's Manual MKTEMP(3)NAME
mktemp - make a unique temporary filename
char *mktemp(char *template);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
mktemp(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500
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.
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
EINVAL The last six characters of template were not XXXXXX.
4.3BSD, POSIX.1-2001. POSIX.1-2008 removes the specification of mktemp().
The prototype is in <unistd.h> for libc4, libc5, glibc1; glibc2 follows the Single Unix Specification and has the prototype in <stdlib.h>.
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).
SEE ALSO mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2008-08-06 MKTEMP(3)