NAME¶

mkstemp - create a unique temporary file

SYNOPSIS¶

#include <stdlib.h>

int mkstemp(char *template);

DESCRIPTION¶

The mkstemp() function generates a unique temporary file name 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 O_EXCL flag, guaranteeing that when mkstemp returns successfully we are the only user.

RETURN VALUE¶

The mkstemp() function returns the file descriptor fd of the temporary file or -1 on error.

ERRORS¶

EINVAL

The last six characters of template were not XXXXXX. Now template is unchanged.

EEXIST

Could not create a unique temporary filename. Now the contents of template are undefined.

BUGS¶

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.

CONFORMING TO¶

BSD 4.3

NOTE¶

The prototype is in <unistd.h> for libc4, libc5, glibc1; glibc2 follows the Single Unix Specification and has the prototype in <stdlib.h>.

SEE ALSO¶

mktemp(3), tmpnam(3), tempnam(3), tmpfile(3)