There's a whole cottage industry of web sites explaining the do {...} while
(0) thing, e.g.
http://www.bruceblinn.com/linuxinfo/DoWhile.htmlOn Fri, Jun 19, 2015 at 11:47 AM, Ivan Gerasimov <ivan.gerasi...@oracle.com> wrote: > > > On 19.06.2015 15:11, Alan Bateman wrote: > >> On 18/06/2015 21:40, Xueming Shen wrote: >> >>> Hi, >>> >>> Please help review the change to resolve the disabled "parentheses" >>> warnings for libzip >>> >>> issue: https://bugs.openjdk.java.net/browse/JDK-8074819 >>> webrev: http://cr.openjdk.java.net/~sherman/8074819 >>> >> Looks okay to me, although I have to admit that parentheses warning is >> new to me (I had to look it up). >> >> > I think this warning would be avoided if ZIP_FORMAT_ERROR weren't defined > as if..else > #define ZIP_FORMAT_ERROR(message) \ > if (1) { zip->msg = message; goto Catch; } else ((void)0) > > Because of this, the compiler sees "if () if () {} else {}" and issues > warning, as it looks errorprone. > > > I believe a more common idiom is using do..while(0) instead: > #define ZIP_FORMAT_ERROR(message) \ > do { zip->msg = message; goto Catch; }while (0) > > Sincerely yours, > Ivan > >
