Question

My program has several modules which is dll.
And one of dlls should notify to the others with some data.
What would you do?

Use shared memory map and event?
or give them a callback function and relaying of program(exe)?

Please let me know the general way.

Answer 1

Here’s a nice trick for communication between modules:

struct A { int a; int b; };
void dll1(A &a);
void dll2(A &a);
int main() {
  A a;
  while(1) {
     dll1(a);
     dll2(a);
  }
}

This will put the whole dll1 to a single function. It can communicate with the other dll by modifying the struct A. Now this will have a problem that main() needs to be modified when you add new dlls to the system. Also struct A will need to be modified when the communication interface between the dlls will change. Removing data from struct A might become impossible, but adding new data will still work fine.