Re: How to automatically update a automatically generated dependence file?

[Peng Yu]

On Fri, Oct 24, 2008 at 4:58 PM, Philip Guenther <address@hidden> wrote:
> On Fri, Oct 24, 2008 at 1:45 PM, Peng Yu <address@hidden> wrote:
> ...
>> I guess. I figure out how to use it. See below for the source code and
>> the Makefile. After running make, I can change nothing3.hpp to
>> nothing2.hpp. The make still runs after the modification.
> ...
>> The first one  's/#.*//'  seems removes the comment, right? But would
>> g++ -MM  generate comments?
>
> If you have a new enough version of gcc, then instead of that complex
> 'sed' statement, you could just pass g++ the -MP option.  That alters
> the -MM option so that it generates the desired stub targets.  Indeed,
> you don't even need the separate MAKEDEPEND line: you can mix -MM and
> -c and gcc/g++ will generate the dependency output *and* compile the
> file in one pass.  Instead of defining your own rule for %.o:%.cpp,
> just use the builtin one and update the COMPILE.cpp variable to
> include the -MM and -MP options:
>
> COMPILE.cpp += -MM -MP
>
> That'll generate .d files, so change the include to
>
> -include $(SRC:.cpp=.d)
>
> That's it.
>
>
> BTW, your makefile seems confused about whether you're doing C or C++,
> as it does some stuff with $(CC) and $(COMPILE.c),  and other stuff
> with g++.  If you're doing C++, then use $(CXX) and $(COMPILE.cpp).
> That includes when linking, so that you can be sure the linker will be
> told about the C++ library bits.

I'm doing C++. I couldn't reproduce what you told me. Would you please
send me the Makefile that incorporates what you said?

Thanks,
Peng