Name
mkstemp — create a unique temporary file
Synopsis
#include <stdlib.h>
int
mkstemp( |
char * | template); |
![[Note]](../stylesheet/note.png) |
Note | ||
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DESCRIPTION
The mkstemp() 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. The file is then created with mode read/write and
permissions 0666 (glibc 2.0.6 and earlier), 0600 (glibc 2.0.7
and later). Since it will be modified, template must not be a string
constant, but should be declared as a character array. The
file is opened with the open(2) O_EXCL flag, guaranteeing that when
mkstemp() returns successfully
we are the only user.
RETURN VALUE
On success, the mkstemp()
function returns the file descriptor of the temporary file.
On error, −1 is returned, and errno is set appropriately.
ERRORS
- EEXIST
-
Could not create a unique temporary filename. Now the contents of
templateare undefined. - EINVAL
-
The last six characters of
templatewere not XXXXXX. Nowtemplateis unchanged.
NOTES
The old behavior (creating a file with mode 0666) may be a security risk, especially since other Unix flavors use 0600, and somebody might overlook this detail when porting programs.
More generally, the POSIX specification does not say
anything about file modes, so the application should make
sure its umask is set appropriately before calling
mkstemp().
The prototype is in <unistd.h>
for libc4, libc5, glibc1; glibc2 follows POSIX.1 and has the
prototype in <stdlib.h>
COLOPHON
This page is part of release 2.79 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/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified Sat Jul 24 18:48:48 1993 by Rik Faith (faithcs.unc.edu) Modified 980310, aeb Modified 990328, aeb |