'mutex': is not a member of 'std' error in msvc

Question

The following code which resides in one of my header files produces the error. There was no problem when the mutex was in a source file and I was using it with extern as a global variable. Thank you!

#include <memory>

struct MyStruct
{
    std::mutex m;
};

Answer 1

you want include the file where std::mutex is located at, in <mutex>

#include <mutex>

struct MyStruct
{
    std::mutex m;
}