MKSTEMP(3)                 Linux Programmer’s Manual                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
       On success, the mkstemp() function returns the file descriptor  of  the
       temporary  file.   On error, -1 is returned, and errno is set appropri-
       ately.

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

       EINVAL The  last  six characters of template were not XXXXXX.  Now tem-
              plate is unchanged.

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
       4.3BSD, 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), tempnam(3), tmpfile(3), tmpnam(3)

GNU                               2001-12-23                        MKSTEMP(3)