mktemp(3) - Linux manual page (original) (raw)
mktemp(3) Library Functions Manual mktemp(3)
NAME top
mktemp - make a unique temporary filenameLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#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 >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
Before glibc 2.12:
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500DESCRIPTION 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](../man3/errno.3.html)_ 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
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **mktemp**() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘STANDARDS top
None.HISTORY top
4.3BSD, POSIX.1-2001. Removed in POSIX.1-2008.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)](../man3/mkstemp.3.html) and [mkdtemp(3)](../man3/mkdtemp.3.html).SEE ALSO top
[mktemp(1)](../man1/mktemp.1.html), [mkdtemp(3)](../man3/mkdtemp.3.html), [mkstemp(3)](../man3/mkstemp.3.html), [tempnam(3)](../man3/tempnam.3.html), [tmpfile(3)](../man3/tmpfile.3.html),
[tmpnam(3)](../man3/tmpnam.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 mktemp(3)
Pages that refer to this page:mktemp(1), mkdtemp(3), mkstemp(3), pmrecord(3), stdio(3), tempnam(3), tmpfile(3), tmpnam(3)