Compiling for 86 & 64 - C++?

Question

Programming

Greetings, I found a source that injects dll into the address space, I need to be able to display my code on the screen of a running program. But I ran into such a problem that I compiled my main program code under x32 and it works under both 64 and 32 bit systems. So why does this program only work 32 if compiled under 32, and only 64 under 64 compiler. Can this program be compiled in such a way that it works under both 32 and 64, if not, how to do the processing from a single application?
PS I think that these applications require a certain bit depth due to working with memory, but this is just my guess.
Code: https://github.com/stephenfewer/ReflectiveDLLInjection

Answer 1

The problem is that you have a dll. And for a dll, the bitness of the program must match the bitness of the dll. You need both versions.

Answer 2

32-bit programs will work on 64-bit systems, at least they should. The difference in allocated memory for variables. And a system with large bits doesn't care how many bits of code, if not more than it can reproduce. If wrong, correct