On 2012-06-07 17:50, hvlems at zonnet.nl wrote: Marc, are you sure ? It means that the assignment gets evaluated as a boolean expression?? No, he's right. The *original* code (not what I wrote further down), is (was): if (port == 0) port == DPORT; Johnny -----Original Message----- From: Marc Chametzky<marc at bluevine.net> Sender: owner-hecnet at Update.UU.SE Date: Thu, 07 Jun 2012 11:44:31 To:<hecnet at Update.UU.SE> Reply-To: hecnet at Update.UU.SESubject: Re: [HECnet] New bridge.c feedback 1171 cc: WARNING File = bridge.c, Line = 684 The indicated expression has no effect. if (port == 0) port == DPORT; ^ Apart from putting in a conditional? DPORT is a constant that I intended for users that compile to be able to change, if they want to. By default is't zero, thus the compiler sees: if (port == 0) port = 0; No, that's not what the compiler is seeing. Instead, it's seeing this: if (port == 0) 1; That's because you have "port == DPORT" (a conditional, not an assignment statement). which is pretty meaningless, and thus something to warn about. But how should I change the code to avoid that? I could (of course) add a check to the if, but that makes it look more complicated, and silly. Oh well, checking if DPORT have been defined to something non-zero is a pretty reasonable solution I think. --Marc