如何在 C 中实现用户模式定时器？

Question

How we can implement our own timer function in Windows without using Library functions? Should we deal with assembly language instructions?

Answer 1

This depends on the precision and resolution you require.

Assuming you need more than second precision, it's popular to wrap/use the RDTSC instruction. But you can also just use the Win32 API, the QueryPerformanceCounter() is widely used for this.

Answer 2

Many APIs like Intel's Threading Building Blocks ( http://threadingbuildingblocks.org ), OpenMP ( http://openmp.org ), SDL ( http://libsdl.org ) or SFML ( http://sfml-dev.org ), and I think also OpenGL ( http://opengl.org ) implement a timer or a wrapper around a timer.

Saying "without using Library functions" is a bit vague: Which library do you mean specifically? In the end, you have to use some library function, or inline assembly, because C++ doesn't have timing functionality in the core language. And without any timer processor or some other timing hardware in whichever form (*), there is no way to tell the time, not vaguely, not exactly.

(*) That includes internet time providers.

Answer 3

get the atomclock time from an internet time service.

else you will always deal with some sort of library-functions with which you can talk to the BIOS, which is the part that makes the tick-tock from the Quartz visible to the OS.