Question

I have been looking for a way to dynamically load functions into c++ for some time now, and I think I have finally figure it out. Here is the plan:

1. Pass the function as a string into C++ (via a socket connection, a file, or something).
2. Write the string into file.
3. Have the C++ program compile the file and execute it. If there are any errors, catch them and return it.
4. Have the newly executed program with the new function pass the memory location of the function to the currently running program.
5. Save the location of the function to a function pointer variable (the function will always have the same return type and arguments, so
   this simplifies the declaration of the pointer).
6. Run the new function with the function pointer.

The issue is that after step 4, I do not want to keep the new program running since if I do this very often, many running programs will suck up threads. Is there some way to close the new program, but preserve the memory location where the new function is stored? I do not want it being overwritten or made available to other programs while it is still in use.

If you guys have any suggestions for the other steps as well, that would be appreciated as well. There might be other libraries that do things similar to this, and it is fine to recommend them, but this is the approach I want to look into — if not for the accomplishment of it, then for the knowledge of knowing how to do so.

Edit: I am aware of dynamically linked libraries. This is something I am largely looking into to gain a better understanding of how things work in C++.

Answer 1

How about a Dynamic Link Library?

These can be linked/unlinked/replaced at runtime.

Or, if you really want to communicated between processes, you could use a named pipe.

edit– you can also create named shared memory.