Re: Turn off C compiler warnings in automake
於 二，2015-06-30 於 09:37 +0200，Thomas Jahns 提到： > On 06/29/15 17:31, Alex Vong wrote: > > Thanks for telling me there is no portable flag for doing so. > > I am now using AC_SUBST() to set the value of STREAM and append ` > > $(STREAM)>/dev/null' to every make command. If the user configure with > > --enable-verbose-compiler, then STREAM will be set to 0, otherwise > > STREAM will be set to 2. This keeps the flexibility. Does it sound > > reasonable? > > I'm not sure if an output redirection on stdin is portable. But I think given > the way you are going about this you could easily set a Makefile variable to > the > full redirection (or none), i.e. lose the >/dev/null and instead make STREAM > be > either '2>/dev/null' or the empty string ''? > > Regards, Thomas Hi Thomas, I tried substituting `2>/dev/null' before but without success. However, I try again just now and find out that if I add a pair of single quotes, then it will work just fine. In short, the following code will work AS_IF([test "x$enable_verbose_compiler" != "xyes"], [AC_SUBST([REDIRECTION], ['2>/dev/null'])] ) Thanks for the suggestion! Cheers, Alex
Re: Turn off C compiler warnings in automake
On 06/29/15 17:31, Alex Vong wrote: Thanks for telling me there is no portable flag for doing so. I am now using AC_SUBST() to set the value of STREAM and append ` $(STREAM)>/dev/null' to every make command. If the user configure with --enable-verbose-compiler, then STREAM will be set to 0, otherwise STREAM will be set to 2. This keeps the flexibility. Does it sound reasonable? I'm not sure if an output redirection on stdin is portable. But I think given the way you are going about this you could easily set a Makefile variable to the full redirection (or none), i.e. lose the >/dev/null and instead make STREAM be either '2>/dev/null' or the empty string ''? Regards, Thomas -- Thomas Jahns HD(CP)^2 Abteilung Anwendungssoftware Deutsches Klimarechenzentrum GmbH Bundesstraße 45a • D-20146 Hamburg • Germany Phone: +49 40 460094-151 Fax:+49 40 460094-270 Email: Thomas Jahns URL:www.dkrz.de Geschäftsführer: Prof. Dr. Thomas Ludwig Sitz der Gesellschaft: Hamburg Amtsgericht Hamburg HRB 39784 smime.p7s Description: S/MIME Cryptographic Signature
Re: Turn off C compiler warnings in automake
於 一，2015-06-29 於 10:00 +0200，Thomas Jahns 提到： > Hi Alex, > > On 06/28/15 16:21, Alex Vong wrote: > > Besides, the code base is quite old and as we know compilers always > > add new warnings. I have asked upstream about fixing the warnings, but > > it seems there is no easy way to fix all of them. So I want to know is > > there a portable way to silent all compiler warnings? Since there are > > lots of warnings even without '-Wall -Wextra'. I want to know how do > > you think about it. > > since you are using gcc, there are -fsyntax-only and -w which should provide > less verbose builds. But there are only very few portable compiler options > (like > -I, -D) and to my knowledge none address warnings. > > You could of course redirect all compiler stderr output to /dev/null and thus > get rid of it, i.e. add 2>/dev/null to your make calls. But this will make > debugging build failures harder later on. > > Regards, Thomas > > Hi Thomas, Thanks for telling me there is no portable flag for doing so. I am now using AC_SUBST() to set the value of STREAM and append ` $(STREAM)>/dev/null' to every make command. If the user configure with --enable-verbose-compiler, then STREAM will be set to 0, otherwise STREAM will be set to 2. This keeps the flexibility. Does it sound reasonable? Cheers, Alex
Re: Turn off C compiler warnings in automake
Hi Alex, On 06/28/15 16:21, Alex Vong wrote: Besides, the code base is quite old and as we know compilers always add new warnings. I have asked upstream about fixing the warnings, but it seems there is no easy way to fix all of them. So I want to know is there a portable way to silent all compiler warnings? Since there are lots of warnings even without '-Wall -Wextra'. I want to know how do you think about it. since you are using gcc, there are -fsyntax-only and -w which should provide less verbose builds. But there are only very few portable compiler options (like -I, -D) and to my knowledge none address warnings. You could of course redirect all compiler stderr output to /dev/null and thus get rid of it, i.e. add 2>/dev/null to your make calls. But this will make debugging build failures harder later on. Regards, Thomas smime.p7s Description: S/MIME Cryptographic Signature
Re: Re: Turn off C compiler warnings in automake
Hi Thomas, Sorry I forget to subscript to the mailing list so I cannot reply, but now I can. May be I should clarify why I want to silent those warnings. Actually, I am working on packaging a GPLed software for a distro. (I am new in both packaging and autotools.) The software does not use a Makefile but provides different compilation flags for different targets. This is of cource inconvienient for end users, so I try to use autotools to guess the host environment and apply the set of suitable compilation flags. Besides, the code base is quite old and as we know compilers always add new warnings. I have asked upstream about fixing the warnings, but it seems there is no easy way to fix all of them. So I want to know is there a portable way to silent all compiler warnings? Since there are lots of warnings even without '-Wall -Wextra'. I want to know how do you think about it. Thanks, Alex
Re: Turn off C compiler warnings in automake
Hello, On 06/22/15 15:44, Alex Vong wrote: Is there any easy way to turn off c compiler warnings (those printed to stderr) portably? From my point of view, the easy way is to write portable code which does not generate warnings. This is also the preferred and recommended way. But automake is quite agnostic in this regard: no part of it (at least that I know of) makes the compiler generate more warnings than the code produces anyway with the selected compiler warning flags. I think you are trying to handle something that is quite external to automake within, which can only lead to problems later on. Please clarify under what circumstances you get unwelcome warnings. If a user of some package builds it with e.g. gcc -Wall, said user is in my opinion entitled to all the warnings that gives. Regards, Thomas smime.p7s Description: S/MIME Cryptographic Signature
Turn off C compiler warnings in automake
Hi everyone, Is there a portable way to silent C compiler warnings in automake? I think of 2 ways of doing it but both ways have serious limitations. 1. hand-craft automake rules with `2>/dev/null' appended on the command limitation: tedious, defeat the purpose of using automake (not _auto_ enough) 2. add `-w' to myprog_CFLAGS limitation: it is GCC-specific and not portable (c99 does not specify this switch) Currently, I am using method 1 (hand-crafting) to achieve per-object flags. However, I learnt that I can use convience library to simulate per-object flags so I rewrite my Makefile.am to use convience library, It looks much cleaner! Is there any easy way to turn off c compiler warnings (those printed to stderr) portably? Thanks all! Alex
