What is the equivalent for strtok_s in QT?

QT is an application framework. strtok_s is a C runtime function. More specifically, strtok_s is Microsoft's secure version of the same standard C non-secure function, strtok. If you're using QT on Windows, just keep using strtok_s because it should be available. If your code is going to be running on Linux, use strtok, and add the pragma that hides/ignores the warning you get during a Visual Studio compile.