C ++ 11的C ++编译问题

Question

I am trying to compile a few C++ files from a make file. I keep on getting this error:

<i> no member named 'to_time_t' in
      'std::__1::chrono::steady_clock'; did you mean
      'std::chrono::system_clock::to_time_t'? 
    time_t tnow = std::chrono::high_resolution_clock::to_time_t(now);

</i>

Then after some research I found out that this is because I'm not using c++ 11. I'm on a MAC OS X 10.10.2. So I installed brew and then installed gcc and g++ 4.9 using brew. However, I still get the same error. Any suggestions? This code runs on a linux machine.

Any help would be appreciated.

Answer 1

to_time_t is a member of system_clock , but not (necessarily) of steady_clock or high_resolution_clock . You are using high_resolution_clock , which on your system, going by the error message, appears to be an alias of steady_clock , not of system_clock . If the code is working for you on another platform, it could be that on that platform, high_resolution_clock is an alias for system_clock , but you can't rely on this always being the case.

The solution is to just use system_clock , if you wan't a time_t from it. system_clock should be at least as high resolution as time_t , so using a potentially higher resolution clock here doesn't buy you anything. Or just use the std::time function in the first place, if you simply want the current time.