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Hi.

Just curiocity,

Because of pre-ANSI C, it is possible to have a function without specifying
return type of a function (which makes the return type 'int', though) and
give no 'return' statement. For example:

foo(int a, int b)
{
int sum;
sum = a + b;
}

void
bar(void)
{
int i = foo(1, 2);
...
}

In above code, the 'i' variable in bar() will have no useful value.
But what does the standard says? I overlooked the ISO C standard, but
found no mention about this problem.

Is this a kind of 'undefined bebavior'? Or 'unspecified behavior'?

If there's wrong point on my explanation, please enlighten me.
Or, could you give me the section number of ISO C document where it deals
with such case?

(Seong-Kook Shin) wrote:

> foo(int a, int b)
> {
> int sum;
> sum = a + b;
> }
>
> void
> bar(void)
> {
> int i = foo(1, 2);
> ...
> }
>
> In above code, the 'i' variable in bar() will have no useful value.
> But what does the standard says?

That it invokes undefined behaviour (which is worse than having no
useful value; it could crash, for example):

# 12 If the } that terminates a function is reached, and the value of
# the function call is used by the caller, the behavior is undefined.

That's from 6.9.1.

Richard