March 2013 - discuss - mailman3.cels.anl.gov

Re: [mpich-discuss] using mpi.h with C++ and warnings that result (ultra-pedantic)
by Jeff Hammond 02 Mar '13

02 Mar '13

On Sat, Mar 2, 2013 at 6:29 AM, Dmitri Gribenko <gribozavr(a)gmail.com> wrote: > On Sat, Mar 2, 2013 at 6:51 AM, Dave Goodell <goodell(a)mcs.anl.gov> wrote: >> On Mar 1, 2013, at 9:57 PM CST, Jeff Hammond wrote: >> >>> I apologize in advance for being ultra-pedantic. >>> >>> I am using MPI in a purely C++ code. Is there a way to make this >>> warning go away? I know at least one MPICH developer who shares my >>> disdain for compiler warnings, so I hope this isn't too unreasonable. >>> >>> Since I am using a C++ compiler, I can't exactly tell it to use C99 mode. >>> >>> /Users/jhammond/eclipse/MPICH2/trunk/install-clang/include/mpi.h:526:9: >>> warning: 'long long' is an extension when C99 mode is not enabled >>> [-pedantic,-Wlong-long] >>> typedef long long MPI_Count; >> >> Don't compile with -pedantic. It's almost never a useful flag. Alternatively, add "-Wno-long-long" if you need other windmills to tilt at. > > I would argue that -pedantic is, in fact, a useful flag. For example, > LLVM and Clang are compiled with -pedantic, but we also add > -Wno-long-long (and a few other flags) to disable warnings about > extensions that are implemented virtually in every compiler. And, > LLVM and Clang have *zero* warnings when compiled with itself. Is there a configure option that will cause MPICH to "typedef long MPI_Count" instead? I compile apps with -pedantic when I want to be absolutely certainly that a non-standard language usage is causing an error. I know MPICH isn't the issue here but that doesn't mean that I don't aspire to compile apps without any warnings. Jeff -- Jeff Hammond Argonne Leadership Computing Facility University of Chicago Computation Institute jhammond(a)alcf.anl.gov / (630) 252-5381 http://www.linkedin.com/in/jeffhammond https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond

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Re: [mpich-discuss] using mpi.h with C++ and warnings that result (ultra-pedantic)
by Dmitri Gribenko 02 Mar '13

02 Mar '13

On Sat, Mar 2, 2013 at 6:51 AM, Dave Goodell <goodell(a)mcs.anl.gov> wrote: > On Mar 1, 2013, at 9:57 PM CST, Jeff Hammond wrote: > >> I apologize in advance for being ultra-pedantic. >> >> I am using MPI in a purely C++ code. Is there a way to make this >> warning go away? I know at least one MPICH developer who shares my >> disdain for compiler warnings, so I hope this isn't too unreasonable. >> >> Since I am using a C++ compiler, I can't exactly tell it to use C99 mode. >> >> /Users/jhammond/eclipse/MPICH2/trunk/install-clang/include/mpi.h:526:9: >> warning: 'long long' is an extension when C99 mode is not enabled >> [-pedantic,-Wlong-long] >> typedef long long MPI_Count; > > Don't compile with -pedantic. It's almost never a useful flag. Alternatively, add "-Wno-long-long" if you need other windmills to tilt at. I would argue that -pedantic is, in fact, a useful flag. For example, LLVM and Clang are compiled with -pedantic, but we also add -Wno-long-long (and a few other flags) to disable warnings about extensions that are implemented virtually in every compiler. And, LLVM and Clang have *zero* warnings when compiled with itself. Dmitri -- main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr(a)gmail.com>*/

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Re: [mpich-discuss] using mpi.h with C++ and warnings that result (ultra-pedantic)
by Dave Goodell 01 Mar '13

01 Mar '13

On Mar 1, 2013, at 9:57 PM CST, Jeff Hammond wrote: > I apologize in advance for being ultra-pedantic. > > I am using MPI in a purely C++ code. Is there a way to make this > warning go away? I know at least one MPICH developer who shares my > disdain for compiler warnings, so I hope this isn't too unreasonable. > > Since I am using a C++ compiler, I can't exactly tell it to use C99 mode. > > /Users/jhammond/eclipse/MPICH2/trunk/install-clang/include/mpi.h:526:9: > warning: 'long long' is an extension when C99 mode is not enabled > [-pedantic,-Wlong-long] > typedef long long MPI_Count; Don't compile with -pedantic. It's almost never a useful flag. Alternatively, add "-Wno-long-long" if you need other windmills to tilt at. -Dave

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using mpi.h with C++ and warnings that result (ultra-pedantic)
by Jeff Hammond 01 Mar '13

01 Mar '13

I apologize in advance for being ultra-pedantic. I am using MPI in a purely C++ code. Is there a way to make this warning go away? I know at least one MPICH developer who shares my disdain for compiler warnings, so I hope this isn't too unreasonable. Since I am using a C++ compiler, I can't exactly tell it to use C99 mode. /Users/jhammond/eclipse/MPICH2/trunk/install-clang/include/mpi.h:526:9: warning: 'long long' is an extension when C99 mode is not enabled [-pedantic,-Wlong-long] typedef long long MPI_Count; It's not like I'm going to lose sleep over this, but I am curious if this is an unavoidable consequence of using the MPI C bindings in C++. Or perhaps it's just because MPI implements MPI_Count using "long long". Thanks Jeff -- Jeff Hammond Argonne Leadership Computing Facility University of Chicago Computation Institute jhammond(a)alcf.anl.gov / (630) 252-5381 http://www.linkedin.com/in/jeffhammond https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond

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