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mkstemp(3) - mkstemp, mkstemp - create a unique temporary file - man 3 mkstemp

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MKSTEMP(3)                 Linux Programmer's Manual                MKSTEMP(3)



NAME
       mkstemp - create a unique temporary file(1,n)

SYNOPSIS
       #include <stdlib.h>

       int mkstemp(char *template);

DESCRIPTION
       The mkstemp() function generates a unique temporary file(1,n) name from tem-
       plate.  The last six characters of template must be  XXXXXX  and  these
       are  replaced with a string(3,n) that makes the filename unique. The file(1,n) is
       then created with mode read(2,n,1 builtins)/write(1,2) 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(3,n) constant, but should  be  declared  as  a
       character array.  The file(1,n) 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(1,n) descriptor fd of the  temporary
       file(1,n) or -1 on error.

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(1,n) 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(1,n) modes, so the application should make sure its umask is set(7,n,1 builtins) appro-
       priately before calling mkstemp.

CONFORMING TO
       BSD 4.3, POSIX 1003.1-2001

NOTE
       The prototype is in(1,8) <unistd.h> for libc4, libc5, glibc1; glibc2 follows
       the Single Unix Specification and has the prototype in(1,8) <stdlib.h>.

SEE ALSO
       mkdtemp(3), mktemp(1,3)(3), tempnam(3), tmpfile(3), tmpnam(3)



GNU                               2001-12-23                        MKSTEMP(3)

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