[DEBATE]int main VS void main?

This is a discussion on [DEBATE]int main VS void main? within the C++ Programming forums, part of the General Programming Boards category; I know the difference between these two setups, but I would like to start a debate thread here to see ...

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    [DEBATE]int main VS void main?

    I know the difference between these two setups, but I would like to start a debate thread here to see what people prefer and why. I've read tutorials that will write the main function as void and others that set it as int and it seems to vary based on person and language. So what is your opinion? I don't really have much of an opinion, however I always write my functions as int main due to force-of-habit; but I rarely ever write return 0;

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    There is no debate. The C++ standard requires main() to return an int.
    If I did your homework for you, then you might pass your class without learning how to write a program like this. Then you might graduate and get your degree without learning how to write a program like this. You might become a professional programmer without knowing how to write a program like this. Someday you might work on a project with me without knowing how to write a program like this. Then I would have to do you serious bodily harm. - Jack Klein

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    What pianorain said. No debate, period. It has NEVER been valid C++. So says the creator of C++.

    /end thread

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    Ahh I wasn't aware of that, but why do other languages do it? It doesn't make sense... so say the programming Gods (C++ developers)

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by sudox
    Ahh I wasn't aware of that, but why do other languages do it? It doesn't make sense... so say the programming Gods (C++ developers)
    Read what rags_to_riches linked to. Why is a value returned from the global main function in C++ in the first place? Is the usage of this return value universal? Are all programming languages used for the same purposes as C++?
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    Quote Originally Posted by sudox View Post
    Ahh I wasn't aware of that, but why do other languages do it? It doesn't make sense... so say the programming Gods (C++ developers)
    The whole point is that a program, when it exits, may have need to return a status value to the environment it ran in. In a lot of environments (eg unix shells, windows command line interpreter, windows itself) the chosen way of doing that is to pass an integer value. The way chosen to return such an integer status in C (and hence C++, which is backward compatible to C in this regard) is by main() returning int.

    In C it is also possible to do that by calling exit(). In C++, that is also possible, but can have unwanted effects (eg not doing stack unwinding) so using exit() is not usually recommended.

    Designers of other programming languages choose to do things in different ways. Clearly, if the designer of some language deems there is no need to return program status to the host environment, there is no need for anything like int main() in that language.
    Right 98% of the time, and don't care about the other 3%.

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    بابلی ریکا Masterx's Avatar
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    i think in the newest versions of compilers , there is no difference between using void or returning an int, cause if you happen to omit that return statement ! the compiler itself will add it!(at backstage)
    atleast mingw (gcc 4.5) does so !
    so to me sticking to the standards never hurt, so i just like this way .
    and also see this thread :
    why do we use int main() instead of void main?
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    Registered User whiteflags's Avatar
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    That you can omit return 0; in main() is really a separate issue. main either returns an int or it does not, and it is dependent on the return type, not the presence of a return statement.

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    C++まいる!Cをこわせ! Elysia's Avatar
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    Quote Originally Posted by Masterx View Post
    i think in the newest versions of compilers , there is no difference between using void or returning an int, cause if you happen to omit that return statement ! the compiler itself will add it!(at backstage)
    atleast mingw (gcc 4.5) does so !
    so to me sticking to the standards never hurt, so i just like this way .
    and also see this thread :
    why do we use int main() instead of void main?
    void main is non-standard and thus should not be used. The fact that many compilers allow this is an err on their part, and it really sucks.
    The fact that you can omit the return statement is independent on the return type in this case. It is perfectly valid in C++ to omit the return statement in main, in which case an implicit return 0 will be added.
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    Quote Originally Posted by Elysia View Post
    void main is non-standard and thus should not be used. The fact that many compilers allow this is an err on their part, and it really sucks.
    It's not actually an error in those compilers - I've yet to come across a C++ (or C) compiler that supports void main() without supporting the standard int main() variants. No compiler vendor can claim their compiler is standard compliant if it does not support int main().

    The C++ standard only requires that a compiler support the int main() entry points. It does not actually disallow other entry points (such as void main()).

    The error - and I agree it sucks - is actually with documentation that uses, or encourages use of, the void main() variants, with an incorrect claim that is standard. A few too many well-known compilers come with documentation that does this.

    The end effect, however, is that programmers who care about portability of their code - or not being seen as ignorant in forums like this one - will only use int main().
    Right 98% of the time, and don't care about the other 3%.

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    When discussing this, you need to distinguish between a hosted and freestanding implementation. Freestanding implementations have much more freedom in how the program's entry point is specified.

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    Regardless of whether an implementation is hosted or freestanding, it is required to support int main() and not required to support other entry points.
    Right 98% of the time, and don't care about the other 3%.

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    The point is that you can use void main and still be compliant if you're using a freestanding implementation that supports it. You're not even required to have a main function to begin with if your compiler supports it. It's not going to be portable, but that's not always a problem.

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    Super Moderator VirtualAce's Avatar
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    Why use void main or even think of using it when the standard clearly requires int main? No debate here.

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    If you never intend to return, void main is just fine. Otherwise, you have no reason to use void main.

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