(PECL gnupg >= 0.5)
gnupg_clearsignkeys — Removes all keys which were set for signing before
成功时返回 TRUE， 或者在失败时返回 FALSE.
Example #1 Procedural gnupg_clearsignkeys() example
<?php
$res = gnupg_init();
gnupg_clearsignkeys($res);
?>
Example #2 OO gnupg_clearsignkeys() example
<?php
$gpg = new gnupg();
$gpg -> clearsignkeys();
?>