Protecting a dedicated function in Visual C plus plus from interruption?

Answer 1

You can only protect a function from interruption by another thread in the same process -- you cannot prevent the operating system from interrupting your program, nor threads in a separate process. To prevent interruption by another thread, use a mutex. The thread that holds the mutex blocks all other threads from holding that same mutex -- they must wait for it to be released by the holder. However, mutexes should only be used when two or more threads need to share information that must be written to by one or more of the threads. They cannot all write simultaneously and you cannot read information that is currently being written. So each thread must obtain the mutex immediately before performing a read or write, and must release it when the read or write is complete. In this way, only one thread has access to the information at any given moment, and all other threads are blocked. This does not prevent interruption, however. You can reduce the chances of interruption simply by raising your thread's priority. Level 0 is the highest priority but is reserved for the operating system, but there are 31 levels available (1 to 31). Use this sparingly and only when absolutely required.