Re: fork() Problem

Matt Stocum (mstocum@adelphia.net)
Wed, 05 May 1999 21:56:20 -0400

>
> The problem is that if anybody writes code like this, they should be
> terminated with extreme prejudice. This is using a gcc compiler bug as
> a feature.
>
> #include <stdio.h>
>
> int foo()
> {
> return 0;
> }
>
> int main()
> {
> int i;
> if(i=foo())
> (void)puts("If this is not seen, it is a compiler BUG!");
>
> return 0;
> }
>

Actually I'm fairly certain it's not a bug but the way C is designed.
When you do an assignment ie i = foo() that assignment returns the value
of foo(). This way you can do x = y = i = foo(). That is a 100% legal
statement in C. Using if(i=foo()) is legal because of this. The
expression i=foo() returns the value of foo() whatever that might be.
In the case of your test program it will be 0 and the if statement will
evaluate to false and you won't see the message. It's not a bug though.

-matt

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