C++: What is SFINAE in C++?

1#include <type_traits>
2
3// Overload for integral types
4template<typename T>
5typename std::enable_if<std::is_integral<T>::value, T>::type
6process(T value) {
7    return value * 2;
8}
9
10// Overload for floating-point types
11template<typename T>
12typename std::enable_if<std::is_floating_point<T>::value, T>::type
13process(T value) {
14    return value + 0.5;
15}
16
17process(42);      // Calls integral overload
18process(3.14);    // Calls floating-point overload
19// process("hi"); // Error — no matching overload