MKTEMP
Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
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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 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- CONFORMING TO
-
- BUGS
-
- SEE ALSO
-
- COLOPHON
-
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