[Rd] C macros and Makevars/package building

[Kurt Hornik]

>>>>> Kasper Daniel Hansen writes:

> Hi
> We are currently embedding a rather large C++ library in R (BioC),  
> and we want some comments on the portability of how we have approach  
> this.

> First of, we are not really able to do much about the portability of  
> the basic library, which of course is the main question :) We have an  
> approach which seems to work, I just want a bit of feedback on it....

> The way we integrate it into R is simply by having a subdirectory  / 
> src/sdk together with a Makevars file. This file basically looks like

> PKG_CPPFLAGS+=\
>    -imacros R_affx_constants.h\
>    -Isdk/files\
>     (... + a lot of other -I statements telling CPP to include  
> subdirectories of src/sdk)

> Then we have a

> SOURCES.SDK = \
>    sdk/files/FileIO.cpp \
>    (... + a lot of other .cpp files)
> SOURCES.OURS = \
>    R_affx_cdf.cpp

> and then finally a

> OBJS=$(SOURCES.SDK:.cpp=.o) $(SOURCES.OURS:cpp:.o)

> We seem to need the last statement since it seems that .cpp is not  
> automatically a C++ suffix (but is it done the "right" way for  
> portability?). We need the -imacro statement in order to include some  
> macros from Rconfig.h (big endian checks) which are then translated  
> from the WORDS_BIGENDIAN used in R to the IS_BIG_ENDIAN used in the  
> library.

> Comments on the portability?

THings like

  OBJS=$(SOURCES.SDK:.cpp=.o)

are portable.  Not sure about the .cpp not being a C++ suffix part; the
generated Makeconf files should contain a rule for

.cpp.o:
        $(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $< -o $@

and the appropriate .SUFFIXES settings.  (Maybe you manipulate
.SUFFIXES?)

Using FOO += something in Make files is not portable.

best
-k