Section: Linux Programmer's Manual (3)
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mkstemp - create a unique temporary file
int mkstemp(char *template);
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,
must not be a string constant, but should be declared as a character array.
The file is opened with the
flag, guaranteeing that when
returns successfully we are the only user.
On success, the mkstemp() function returns the file descriptor
of the temporary file.
On error, -1 is returned, and
is set appropriately.
Could not create a unique temporary filename.
Now the contents of template are undefined.
The last six characters of template were not XXXXXX.
Now template is unchanged.
The old behaviour (creating a file with mode 0666) may be
a security risk, especially since other Unix flavours 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
The prototype is in
for libc4, libc5, glibc1; glibc2 follows the Single Unix Specification
and has the prototype in
- RETURN VALUE
- CONFORMING TO
- SEE ALSO
linux.jgfs.net manual pages