I'm pulling my hair out trying to work this one out.

heres the code :

This function is called if plr.menu is set to 1 (or display the war menu) which works fine.
However whenever I try to set the plr.researching variable to 1 it automatically resets to 0. I've check all other files and there is no where that researching is being set at all. Researching will only stay set if I am holding the mouse button down or have the R key checked.

Any ideas?

Don't pass entire structs as parameters. Either pass a pointer, or (if using C++) a reference. I don't know if that's related to your problem, but I don't see anything in that code that'd cause it to reset (a stack overflow could cause you to start getting memory corruption, though). Double-check everywhere your check researching == 0 and make sure you aren't accidently doing researching = 0.

That's whats bugging me. The only place that researching is being used is in this function.

If you code in C:

void draw_war_menu(BITMAP *buf,player *plr) {
   ...
   plr->whatever = something;
}

// call it like this:
draw_war_menu(buffer, &player);

If you code in C++ the above will work but this is prefered:

void draw_war_menu(BITMAP *buf,player &plr) {
   ...
   plr.whatever = something;
}

// call it like this:
draw_war_menu(buffer, player);

Btw, that's what Kitty Cat said in case you didn't understand.

EDIT: And in case you still don't understand, I'll try to explain. When you pass your player object by value, a temporary copy is made. You modify this temporary copy in your draw_war_menu function. When this function returns, the temporary copy is destroyed. So nothing gets reset to 0 because you never changed the original in the first place. You were modifying a temporary copy.

Also you might notice if you pay close attention, that your code not only doesn't do what you want, but will also be a bit slower than the proper way. Because making a temporary copy and then destroying it takes more time than not making a temporary copy and then destroying it.

And one more thing, you should always separate logic from drawing! Your code mixes logic and drawing. This is not good.

If you are passing player ply, then won't it be passing a copy to the function? In this case you will only be setting the copy's variable and not the original.

Indeed, you are passing your structure's values. Use pointers or references.

Thanks for all the advice.
I'll be starting the project again from scatch, so I'll keep it all in mind.

I think it might also have something to do with the fact that the plr struct is a global variable as well. Would this cause a conflict using player plr as a global and player plr as a parameter?

No conflicts that I know of. Its a bit messy, but thats about it.

OT: Am I the only one who wants to post: "No, use HTML" ?