From mboxrd@z Thu Jan 1 00:00:00 1970 From: Donald Koch To: Nick Clifton Cc: egcs@cygnus.com Subject: Re: Should warnings be issued for unrecognised pragmas ? Date: Fri, 17 Oct 1997 14:36:00 -0000 Message-id: <199710171859.OAA01700@beau_jos.cognex.com> References: <199710162311.QAA24209@elmo.cygnus.com> X-SW-Source: 1997-10/msg00734.html > I am currently writting a patch for gcc2 that implements a new command > line option '-wunrecognised-pragmas' which will cause warning messages > to be generated when GCC encounters pragmas which is does not handle. > At the moment this patch also enables these warnings if -Wall is > enabled, expect for the case where the pragmas are in system header > files. Is this the right thing to do ? If you mean by "this", enabling it with -Wall, no. Consider the use of "-Werror -Wall", where the desired effect is to make sure there are no iffy constructs in the code; would failure to compile because there was an unrecognized pragma which is needed for some other compiler/platform be desirable? -Wall check for too many useful things, which is what it should do. > The '89 ANSI C standard says: > "Any pragma that is not recognized by the implementation is ignored." > > It is my opinion that "ignoring" is not the same as "not issuing a > warning", if such warnings have been requested, and that it is > important to know if a compiler is ignoring pragmas as they may have > been intended to affect code generation. > > Any comments ? > > Nick Clifton Otherwise, I think the '-wunrecognised-pragmas' could be very useful; e.g., for the case where you only have one platform/compiler and an unrecognized pragma indicates a typo. -d