function cphase( z ) {
	return addon( z );
}
Computes the argument of a double-precision complex floating-point number in radians.

@private
@param {Complex128} z - complex number
@returns {number} argument

@example
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var phi = cphase( new Complex128( 5.0, 3.0 ) );
// returns ~0.5404