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 ( !empty( $path ) && is_string( $path ) && strpos( $path, '..' ) === false )
		$url .= ltrim( $path, '/' );

	return apply_filters( 'admin_url', $url, $path, $blog_id );
}
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