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Manual for mktemp - man 3 mktemp

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



NAME
       mktemp(1,3) - make a unique temporary file(1,n) name

SYNOPSIS
       #include <stdlib.h>

       char *mktemp(1,3)(char *template);

DESCRIPTION
       The  mktemp(1,3)() 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. Since it
       will be modified, template must not be a string(3,n) constant, but should be
       declared as a character array.

RETURN VALUE
       The  mktemp(1,3)()  function  returns NULL on error(8,n) (template did not end in(1,8)
       XXXXXX) and template otherwise.  If the call was successful,  the  last
       six  bytes  of  template will have been modified in(1,8) such a way that the
       resulting name is unique (does not exist  already).  If  the  call  was
       unsuccessful, template is made an empty string.


ERRORS
       EINVAL The last six characters of template were not XXXXXX.

CONFORMING TO
       BSD 4.3. POSIX dictates tmpnam(3).

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>.

BUGS
       Never use mktemp(1,3)(). Some implementations follow  BSD  4.3  and  replace
       XXXXXX  by  the current process id and a single letter, so that at most
       26 different names can be returned.  Since on the one  hand  the  names
       are  easy to guess, and on the other hand there is a race between test-
       ing whether the name exists and opening the file(1,n), every use of mktemp(1,3)()
       is a security risk.  The race is avoided by mkstemp(3).

SEE ALSO
       mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)



GNU                               1993-04-03                         MKTEMP(3)

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