similar concept in c++:
float inf = std::numeric_limits<float>::infinity();
// setup example data:
Mat_<float> m(3,3);
m << 1,2,inf,4,inf,6,7,inf,inf;
// mask all values with inf:
Mat mask = m==inf;
// change all inf vals to 17:
m.setTo(17, mask);
cout << m << endl;
[1, 2, 17;
4, 17, 6;
7, 17, 17]