(PHP 5 >= 5.3.0)
hash_copy — Copy hashing context
Hashing context returned by hash_init().
Returns a copy of Hashing Context resource.
Example #1 hash_copy() example 以上例程会输出：
<?php
$context = hash_init("md5");
hash_update($context, "data");
/* copy context to be able to continue using it */
$copy_context = hash_copy($context);
echo hash_final($context), "
";
hash_update($copy_context, "data");
echo hash_final($copy_context), "
";
?>
8d777f385d3dfec8815d20f7496026dc
511ae0b1c13f95e5f08f1a0dd3da3d93