DebugBreak and __debugbreak
You can call the DebugBreak Win32 function or the __debugbreak intrinsic at any point in your code. DebugBreak and __debugbreak have the same effect as setting a breakpoint at that location.
Because DebugBreak is a call to a system function, system debug symbols must be installed to ensure the correct call stack information is displayed after breaking. Otherwise, the call stack information displayed by the debugger may be off by one frame. If you use __debugbreak, symbols are not required.