mktemp - make a unique temporary filename
char *mktemp(char *template);
Feature Test Macro Requirements for glibc (see feature_test_macros
Never use this function
- 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
; see BUGS.
() function generates a unique temporary filename from
. 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.
() 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,
is set to indicate the error.
- The last six characters of template were not XXXXXX.
For an explanation of the terms used in this section, see attributes
4.3BSD, POSIX.1-2001. POSIX.1-2008 removes the specification of mktemp
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