[DVDnav-discuss] [PATCH] Fix parallel jobs; sources need version.h

[Nico Sabbi]

Il Wednesday 30 April 2008 20:04:59 Dan Nicholson ha scritto:
> On Wed, Apr 30, 2008 at 9:01 AM, Nico Sabbi <Nicola.Sabbi at poste.it> wrote:
> >
> > On Wednesday 30 April 2008 14:55:06 Dan Nicholson wrote:
> >  > On Wed, Apr 30, 2008 at 12:57 AM, Nico Sabbi <Nicola.Sabbi at poste.it>
> >  wrote:
> >  > > On Monday 28 April 2008 23:53:38 Dan Nicholson wrote:
> >  > >  > ---
> >  > >  >  Makefile |    2 ++
> >  > >  >  1 files changed, 2 insertions(+), 0 deletions(-)
> >  > >  >
> >  > >  > diff --git a/Makefile b/Makefile
> >  > >  > index fcc3940..85108e5 100644
> >  > >  > --- a/Makefile
> >  > >  > +++ b/Makefile
> >  > >  > @@ -81,6 +81,8 @@ endif
> >  > >  >  version.h:
> >  > >  >       sh $(SRC_PATH)/version.sh $(SRC_PATH)
> >  > >  >
> >  > >  > +$(SRCS) $(DVDREAD_SRCS): version.h
> >  > >  > +
> >  > >  >
> >  > >  >  # General targets
> >  > >
> >  > >  can you explain, please?
> >  > >  If I read the dependencies all .c files already depend on
> >  > > version.h
> >  >
> >  > They don't. The library $(SHLIB) depends on version.h. Since that's
> >  > the first target, version.h gets built immediately. However, if you
> >  > have multiple jobs (-j3 or whatever), make will also begin building
> >  > the .c files without waiting for version.h to be built. This causes
> >  > a race condition if any .c file including config.h or version.h is
> >  > built before version.h is created.
> >  >
> >  > You can see if the .c files depend on version.h pretty easily. Run
> >  > `make -d dvdnav.o' and redirect the log somewhere. It will show in
> >  > detail the prerequisites for the target dvdnav.o. For me, version.h
> >  > never comes up until after the patch above. If this is a clean
> >  > checkout (i.e., you've only run configure2), `mkdir obj && make
> >  > dvdnav.o' will bomb like this:
> >  >
> >  > cd obj && gcc -MD -g -O2 -march=i686 -pipe  -Wall -funsigned-char
> >  > -I/home/dan/scm/libdvdnav -I"/home/dan/scm/libdvdnav"/src
> >  > -I"/home/dan/scm/libdvdnav"/src/vm -DDVDNAV_COMPILE
> >  > -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -DHAVE_CONFIG_H
> >  > -DHAVE_DLFCN_H -I"/home/dan/scm/libdvdnav"/src/dvdread -c -o
> >  > dvdnav.o /home/dan/scm/libdvdnav/src/dvdnav.c
> >  > In file included from /home/dan/scm/libdvdnav/src/dvdnav.c:25:
> >  > /home/dan/scm/libdvdnav/config.h:2:21: error: version.h: No such
> >  > file or directory
> >  >
> >  > With the patch, it properly generates version.h first, and this
> >  > works.
> >  >
> >
> >  ok and sorry for the delay: I've been busy all week. Today or tomorrow
> >  I'll commit your patch(es)
> 
> No problem. Sorry for not giving many details initially.
> 
> --

applied, thanks