How can I print value of std::atomic?

Question

I am using std::atomic in my program. How can I print its value using printf? It doesn't work if I just use %u. I know I can use std::cout, but my program is littered with printf calls and I don't want to replace each of them. Previously I was using unsigned int instead of std::atomic, so I was just using %u in the format string in my printf call, and therefore printing worked just fine.

The error I'm getting when trying to print the std::atomic now in place of the regular unsigned int is:

error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 2 has type ‘std::atomic’ [-Werror=format=]

user_217945 · Answer

another option, you can use the atomic variable's load() method. E.g.:

std::atomic a = { 42 };
printf("%u
", a.load());

How can I print value of std::atomic<unsigned int>?

2 Answers