Re: Request for review of failing makefile

[Maxim Yegorushkin]

On 18/12/09 14:04, David Aldrich wrote:
> Hi Maxim and Bart
>
> Thanks very much for reviewing my makefile. Your suggestion of an extra command
> did indeed solve my problem. That's great.

Pleasure.

> My reason for not replying sooner is that I am testing other parts of the
> makefile.
>
> What I sent was actually a simplified version. The real version had:
>
> .PHONY : release
>         release : $(OBJDIR_R)/$(EXEFILE)
> <snip>
> $(OBJDIR_R)/$(EXEFILE) : $(ARCHIVES_R)
>         $(CXX) -o $(OBJDIR_R)/$(EXEFILE) -ldl 
> -Wl,-whole-archive,-export-dynamic $(ARCHIVES_R) $(EXTRA_LIBS_R)
> <snip>
> $(ARCHIVES_R) $(ARCHIVES_D) : versioninfo $(STATIC_LIBS) $(DYNAMIC_LIBS)
>
> Now $(ARCHIVES_R) contains the paths of the static libraries. I can see
> no reason why this should depend on $(DYNAMIC_LIBS) (some code of the
> program is linked in dynamic libraries so that we can selectively load it).
> So I think better rules would be:
>
> .PHONY : release
>         release : $(OBJDIR_R)/$(EXEFILE) $(DYNAMIC_LIBS) versioninfo
> <snip>
> $(OBJDIR_R)/$(EXEFILE) : $(ARCHIVES_R)
>         $(CXX) -o $(OBJDIR_R)/$(EXEFILE) -ldl 
> -Wl,-whole-archive,-export-dynamic $(ARCHIVES_R) $(EXTRA_LIBS_R)
> <snip>
> $(ARCHIVES_R) $(ARCHIVES_D) : $(STATIC_LIBS)

Well, whether your static libraries depend on the dynamic libraries 
depends on whether this dependency really exists. It is conceivable that 
any of your static libraries could load any of the dynamic libraries at 
run-time, so that in this case such a dependency does exist. However, it 
is likely that this dependency have already been specified in the 
makefile that builds the static and dynamic libraries as it should, so 
that it does not need to be repeated in another makefile.

> (versionInfo is a small utility that we also want built.

versionInfo could simply be a plain text file with versions of 
executables and shared libraries. The link rule would extract the 
corresponding version of the binary being linked from that text file 
(grep, sed, awk, ...) and embed that version into the binary. Updating 
this text file would trigger a relink (a complete relink though, so it 
should not be updated too often). Something like:

lib/libsome.so 1.2.3
bin/some_app 2.3.4

--
Max