Retrieve the url to the admin area for a given site.

Signature

get_admin_url( $blog_id = null, $path = '', $scheme = 'admin' )
blog_id
 (int) (optional) Blog ID. Defaults to current blog.
Default: null
path
 (string) Optional path relative to the admin url.
Default: ''
scheme
 (string) The scheme to use. Default is 'admin', which obeys force_ssl_admin() and is_ssl(). 'http' or 'https' can be passed to force those schemes.
Default: 'admin'

Return

(string) Admin url link with optional path appended.

Source

function get_admin_url( $blog_id = null, $path = '', $scheme = 'admin' ) {
	$url = get_site_url($blog_id, 'wp-admin/', $scheme);

	if ( $path && is_string( $path ) )
		$url .= ltrim( $path, '/' );

	/**
	 * Filter the admin area URL.
	 *
	 * @since 2.8.0
	 *
	 * @param string   $url     The complete admin area URL including scheme and path.
	 * @param string   $path    Path relative to the admin area URL. Blank string if no path is specified.
	 * @param int|null $blog_id Blog ID, or null for the current blog.
	 */
	return apply_filters( 'admin_url', $url, $path, $blog_id );
}
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