(PHP 5 >= 5.1.0)
posix_mknod — Create a special or ordinary file (POSIX.1)
$pathname
   , int $mode
   [, int $major = 0
   [, int $minor = 0
  ]] )Creates a special or ordinary file.
pathnameThe file to create
mode
       This parameter is constructed by a bitwise OR between file type (one of
       the following constants: POSIX_S_IFREG,
       POSIX_S_IFCHR, POSIX_S_IFBLK,
       POSIX_S_IFIFO or
       POSIX_S_IFSOCK) and permissions.
      
major
       The major device kernel identifier (required to pass when using
       S_IFCHR or S_IFBLK).
      
minorThe minor device kernel identifier.
   Returns TRUE on success or FALSE on failure.
  
Example #1 A posix_mknod() example
<?php
$file = '/tmp/tmpfile';  // file name
$type = POSIX_S_IFBLK;   // file type
$permissions = 0777;     // octal
$major = 1;
$minor = 8;              // /dev/random
if (!posix_mknod($file, $type | $permissions, $major, $minor)) {
    die('Error ' . posix_get_last_error() . ': ' . posix_strerror(posix_get_last_error()));
}
?>