Re: comments in make variable definition
* Stefano Lattarini wrote on Wed, Dec 22, 2010 at 06:17:47PM CET: [stemming from discussion about automake bug#7657: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7657] On Tuesday 21 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Tue, Dec 21, 2010 at 01:55:39PM CET: On Sunday 19 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Fri, Dec 17, 2010 at 12:19:40PM CET: xmandir = $(mandir) # we want info files installed in $(mandir) because ... xman_TEXINFOS = foo.texi (And the inline comment is of course not ok ;-) (Maybe it's time to deprecate them too in the manual ...) I don't see how they were ever not problematic. Well, at least given the autoconf.texi general warnings about comments in makefiles. Ah, but AFAIK, make comments are problematic only in makefile *rules*, not in variable definitions: VAR = foo bar # a probably portable comment tgt:; touch $@ # a bad unportable commen Not quite. The above comment in the variable definition is not unportable, but it is unobvious: For a Posix make, the above defines VAR to be 'foo bar '. Note the trailing space! If automake parses it differently, then that is a semantic difference to how Posix make reads its input. (We may have a couple such differences already, but in general, they are not desirable.) What you are hinting at is # signs within quoted parts of a variable definition, like '#' or # or more complex things. Posix notes: Because of widespread historical practice, interpreting a '#' number sign inside a variable as the start of a comment has the unfortunate side effect of making it impossible to place a number sign in a variable, thus forbidding something like: CFLAGS = -D COMMENT_CHAR='#' but most modern makes treat quoted content differently. (No, I have not done research as to how exactly quoted content is defined by the various make implementations. I'm sure there are variations here as well.) Cheers, Ralf
Re: comments in make variable definition
On Wed, Dec 22, 2010 at 06:17:47PM +0100, Stefano Lattarini wrote: On Tuesday 21 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Tue, Dec 21, 2010 at 01:55:39PM CET: On Sunday 19 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Fri, Dec 17, 2010 at 12:19:40PM CET: xmandir = $(mandir) # we want info files installed in $(mandir) because ... xman_TEXINFOS = foo.texi (And the inline comment is of course not ok ;-) (Maybe it's time to deprecate them too in the manual ...) I don't see how they were ever not problematic. Well, at least given the autoconf.texi general warnings about comments in makefiles. Ah, but AFAIK, make comments are problematic only in makefile *rules*, not in variable definitions: VAR = foo bar # a probably portable comment tgt:; touch $@ # a bad unportable commen Try also to search: ^[^\t#].*=.*\s# file:^Makefile\.am$ with google code search (not many entries, luckily, but still). Regards, Stefano Actually it is not always ok. FreeBSD's make chokes on it in some instances: VAR = foo # this comment is ok VAR = foo \ # this is also ok VAR = foo \ # this is ok \ # - Unassociated shell command Also, it will break $(am__append*) variables, but that is not relevant in this case. -- Pippijn van Steenhoven signature.asc Description: Digital signature
comments in make variable definition
[dropping debbugs, adding automake] [stemming from discussion about automake bug#7657: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7657] On Tuesday 21 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Tue, Dec 21, 2010 at 01:55:39PM CET: On Sunday 19 December 2010, Ralf Wildenhues wrote: * Stefano Lattarini wrote on Fri, Dec 17, 2010 at 12:19:40PM CET: xmandir = $(mandir) # we want info files installed in $(mandir) because ... xman_TEXINFOS = foo.texi (And the inline comment is of course not ok ;-) (Maybe it's time to deprecate them too in the manual ...) I don't see how they were ever not problematic. Well, at least given the autoconf.texi general warnings about comments in makefiles. Ah, but AFAIK, make comments are problematic only in makefile *rules*, not in variable definitions: VAR = foo bar # a probably portable comment tgt:; touch $@ # a bad unportable commen Try also to search: ^[^\t#].*=.*\s# file:^Makefile\.am$ with google code search (not many entries, luckily, but still). Regards, Stefano
