Using the mathematics library GLM, I use this code to combine the euler angle rotations to a rotation matrix.
#include <GLM/gtc/matrix_transform.hpp>
using namespace glm;
mat4 matrix = rotate(mat4(1), X, vec3(1, 0, 0))
* rotate(mat4(1), Y, vec3(0, 1, 0))
* rotate(mat4(1), Z, vec3(0, 0, 1));
Does this result in an euler angle sequenze of XYZ or ZYX? I am not sure since matrix multiplication behave not the same as scalar multiplications.