mkstemp (3)

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 tem-
       plate.  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 tem-
              plate is unchanged.

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

NOTES

       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 appro-
       priately before calling mkstemp.

CONFORMING TO

       BSD 4.3, POSIX 1003.1-2001

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

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

GNU                               2001-12-23                        mkstemp(3)