VEC4_LEN

Evaluates to the number of components of a Vec4.

This symbol is useful when declaring a C array of floating point values to be used with init_from_float and to_float, e.g.

	float v[GRAPHENE_VEC4_LEN];

	// vec is defined elsewhere
	graphene_vec4_to_float (&vec, v);

	for (int i = 0; i < GRAPHENE_VEC4_LEN; i++)
		fprintf (stdout, "component %d: %g\n", i, v[i]);