return 0;

[Thuraya]

Hi,

Why some compilers do not complain about missing the return 0 statement ?

[btucho]

well some compilers seem to have a default 0 value, to when a function declares its return type as int and does not actually have a return statement.

[kbw]

well some compilers seem to have a default 0 value

Not true.

A C++ compiler should report an error.

[btucho]

well atleast one - used by dev c++ does not - and uses 0 as default value.

when tried :

int foo()
{
//whatever... - no return statement.
}

int main()
{
int b=5;
b=foo();
cout<<b<<endl;
}

no errors, and output is 0.

i know dev is not that good of an example but still..


this is just a result of some testing, i dont really have an answer i am sure of, so i'll just say i dont want anyone getting it wrong because of me.. these are just conclusions i made after trying the above code on a c++ compiler.

[kbw]

You get whatever's in EAX at the time in this instance. There is no default.

[D80DSL3A]

There is an exception for main() permitting omission of the return statement.
I found this at http://en.wikipedia.org/wiki/Main_function_%28programming%29

From this article:

In case a return value is not defined by the programmer, an implicit return 0; at the end of the main() function is inserted by the compiler; this behavior is required by the C++ standard.

[Thuraya]

Thanks all :)