How to get the time in milliseconds in C++

Question

In Java you can do this:

long now = (new Date()).getTime();

How can I do the same but in C++?

Answer 1

Because C++0x is awesome

namespace sc = std::chrono;

auto time = sc::system_clock::now(); // get the current time

auto since_epoch = time.time_since_epoch(); // get the duration since epoch

// I don't know what system_clock returns
// I think it's uint64_t nanoseconds since epoch
// Either way this duration_cast will do the right thing
auto millis = sc::duration_cast<sc::milliseconds>(since_epoch);

long now = millis.count(); // just like java (new Date()).getTime();

This works with gcc 4.4+. Compile it with --std=c++0x. I don't know if VS2010 implements std::chrono yet.