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NAME

       mktemp - make a unique temporary filename

SYNOPSIS

       #include <stdlib.h>

       char *mktemp(char *template);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mktemp():
           Since glibc 2.12:
               (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L)
                   || /* Glibc since 2.19: */ _DEFAULT_SOURCE
                   || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
           Before glibc 2.12:
               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500

DESCRIPTION

       Never use this function; see BUGS.

       The  mktemp()  function generates a unique temporary filename from template.  The last six
       characters of template must be XXXXXX and these are replaced with a string that makes  the
       filename  unique.   Since it will be modified, template must not be a string constant, but
       should be declared as a character array.

RETURN VALUE

       The mktemp() function always returns template.  If a unique name was created, the last six
       bytes  of template will have been modified in such a way that the resulting name is unique
       (i.e., does not exist already) If a unique name could not be created, template is made  an
       empty string, and errno is set to indicate the error.

ERRORS

       EINVAL The last six characters of template were not XXXXXX.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────┬───────────────┬─────────┐
       │InterfaceAttributeValue   │
       ├──────────┼───────────────┼─────────┤
       │mktemp()  │ Thread safety │ MT-Safe │
       └──────────┴───────────────┴─────────┘

CONFORMING TO

       4.3BSD, POSIX.1-2001.  POSIX.1-2008 removes the specification of mktemp().

BUGS

       Never  use mktemp().  Some implementations follow 4.3BSD 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
       testing whether the name exists and opening the file, every use of mktemp() is a  security
       risk.  The race is avoided by mkstemp(3) and mkdtemp(3).

SEE ALSO

       mktemp(1), mkdtemp(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)

COLOPHON

       This  page  is  part of release 4.16 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.