C++Linking Classes/.cpp files to run one after other?

FinalDecap · 04-11-2010, 11:13 AM

This is probably a really stupid thing to ask considering the development I'm doing (effectivly creating a virus scanner), but how do I link classes/cpp files?

I have 3 applications/sections that I can compile/combine with a makefile, that's fine, but I need them to run 1, 2, 3 once the output from the makefile is done.

Currently the only section to actually run is whichever I have "main" in and obviously if I put that into all three, they won't compile as one.

I've been looking all over the place at all sorts, header files and such, but there is no mention of how to actually do this although I'm sure it must be possible. I'm used to being able to do this in Java and I'm sure I've seen C++ applications do it, but not worked out how.

I have 3x .cpp files which are combined into one using a makefile:

Code:

# Virus Scanner

scanner.out : ProgramList.o MD5Hash.o HazardCheck.o
	g++ -o scanner.out ProgramList.o MD5Hash.o HazardCheck.o /usr/lib/libstdc++.so.5 CONFIG/rudeconfig.lib HASH/src/libhl++.a

ProgramList.o: PROGRAMS/ProgramList.cpp
	g++ -c PROGRAMS/ProgramList.cpp

MD5Hash.o: HASH/MD5Hash.cpp
	g++ -c HASH/MD5Hash.cpp

HazardCheck.o: CONFIG/HazardCheck.cpp CONFIG/hazard.conf
	g++ -c CONFIG/HazardCheck.cpp 

clean:
	rm *.o scanner.out

#END OF MAKE FILE

scanner.out will run, but only whichever .cpp has "main()" in it, so the other two are defunct but are included within scanner.out. If I compile the three files separately I end up with three programs, but I need them to work together as a single application.

I'm doing all my work on Linux using vi to edit the files, but I assume what I want to do is generic between systems.

Any/All help is appreciated.

JohnGraham · 04-11-2010, 11:27 AM

You don't want multiple main() functions, you want three functions you can call from main(). Or you could go down a purer OO/Java-style method of giving each class a static main() method, and go through each class calling it.

Either way, you have to do-it-yourself - there are hacks that would allow you to do it in gcc (e.g. using the constructor attribute) but that would wreck portability, and is certainly not what that's designed for.

FinalDecap · 04-12-2010, 02:22 AM

Quote:

Originally Posted by JohnGraham

You don't want multiple main() functions, you want three functions you can call from main(). Or you could go down a purer OO/Java-style method of giving each class a static main() method, and go through each class calling it.

These two options are essentially what I was then planning to do (either of them) but didn't know how to implement either of them...it's been a while since I did any coding and I was never one to be strong on coding practices/OOP which I know is bad and has given me the problem here.

I've had a few other opinions elsewhere and have decided the easiest course of action is for me to create another function/file that contains a main() an calls on the other three.

The idea is that this should be portable between systems with minimal recoding which obviously if I managed to smear them together in some really awkward way then I'd be a bit stuck.

Cheers for the help.