WordPress at a glance
function is not described

edit_link() WP 2.0.0

Updates or inserts a link using values provided in $_POST.

No Hooks.

Return

Int/WP_Error. Value 0 or WP_Error on failure. The link ID on success.

Usage

edit_link( $link_id );
$link_id(int)
ID of the link to edit.
Default: 0

Code of edit link: wp-admin/includes/bookmark.php VER 5.0.3

<?php
function edit_link( $link_id = 0 ) {
	if ( ! current_user_can( 'manage_links' ) ) {
		wp_die(
			'<h1>' . __( 'You need a higher level of permission.' ) . '</h1>' .
			'<p>' . __( 'Sorry, you are not allowed to edit the links for this site.' ) . '</p>',
			403
		);
	}

	$_POST['link_url'] = esc_html( $_POST['link_url'] );
	$_POST['link_url'] = esc_url($_POST['link_url']);
	$_POST['link_name'] = esc_html( $_POST['link_name'] );
	$_POST['link_image'] = esc_html( $_POST['link_image'] );
	$_POST['link_rss'] = esc_url($_POST['link_rss']);
	if ( !isset($_POST['link_visible']) || 'N' != $_POST['link_visible'] )
		$_POST['link_visible'] = 'Y';

	if ( !empty( $link_id ) ) {
		$_POST['link_id'] = $link_id;
		return wp_update_link( $_POST );
	} else {
		return wp_insert_link( $_POST );
	}
}