Thread: ending a program

Yep, std::exit( int ) in <cstdlib> .

Originally posted by Nuke
Isn't it also in stdlib.h?

As I understand it, C standard headers (including stdlib.h) are best used in C++ by dropping the ".h" and putting a "c" in front of it. This also puts the functions into the namespace "std". Although your way works, it's deprecated.

anyway, isn't it easier just to return 0?

You can, but only if you're in main. What if you call another function and decide (for some reason) to exit from there?

>Isn't it also in stdlib.h?
stdlib.h or cstdlib. However, take note that when you use cstdlib, everything will be in the std namespace.

>anyway, isn't it easier just to return 0?
From the control of main, yes. From elsewhere it's not so easy to return in one fell swoop without lots of annoying flags (exit is easier then). Also, for some compilers, exit is the only way to be sure that the return code you pass is not discarded. Many compilers will simply return 0 even if your code specifies a different return code.

Many compilers will simply return 0 even if your code specifies a different return code.

Really? What compilers do this, and why (it's so easy not to do it).

>What compilers do this
Pretty much any compiler that allows void main probably does so. The standard requires that main be invoked as if called like this:

Code:

exit(main(argc, argv);

However, some compilers (mostly older ones) do it more like this:

Code:

main(argc, argv);
exit(0);

So if you have to have a useful exit code, it's more portable (in reality) to use the exit function instead of the return keyword.

I know for sure that VC++ does not do it, although it allows void main.

Don't know about exotic compilers though, don't really care for them.

You shouldn't use void main( ) in the first place. It is nowhere in the standard for C++, and I'm pretty sure its not allowed in C either.

The main time you want to use exit( ) is if you want to quit the program from a function other than main( ). In this case, a simple return statement won't do, so you have to use the exit( ) command.