Re: [Boost-users] compiling boost.signals without exception

From: Rene Rivera (grafik.list_at_[hidden])
Date: 2005-09-16 22:58:49

Martin Sarrazac wrote:
> Hi,
> compiler:  mingw gcc 3.4.4
> I would like to compile boost.signals without exception handling,  I 
> read somewhere about the <exception-handling> feature so I tried:
> 
> bjam --builddir=c:\temp -sTOOLS=mingw "-sBUILD=debug 
> <exception-handling>off <runtime-link>dynamic <threading>single" 
> --libdir=C:\boost\lib\noe --with-signals -d2 install
> 
> without success, it compiles fine but not without exception handling. 
> specifically the -fno-exception command line option should be passed to 
> gcc and it's not.
> 
> I had a look at tools/build/v1/gcc-tools.jam and I found this line for 
> rtti support for instance:
> 
> flags gcc C++FLAGS <rtti>off : -fno-rtti ;
> 
> However there is nothing equivalent for exceptions...

Good job on the investigation :-) Very few users bother to go this far. 
Yes even though "<exception-handling>" is defined there is no handling 
for it in the GCC toolset. It's easy enough to add that you could easily 
do it, as it's basically the same as the <rtti> flag you found.

But it is also possible to specify any additional compile flags with the 
  -sBUILD setting. One just needs to use the <cxxflags> feature.

> On a side note I don't know how to give a new tag to the 'no exception' 
> version of the library, so I compiled it in an other directory 
> (--libdir=C:\boost\lib\noe). However I would much prefer to give it a 
> specific name.

Now that's a tough one. There's no non-intrusive way to change the tags. 
You would need to modify the Boost.Build code some. The place to do it 
at would be in the "tools/build/v1/boost-base.jam" file. In there 
there's a "rule common-variant-tag ..." which you would need to change 
to add another letter to the tags when a build with 
<exception-handling>off shows up.

> Is there somewhere information about all the -sBUILD 
> flags can be found? Can't seem to locate it.

The only complete docs on that are on the source itself: 
http://www.boost.org/tools/build/v1/features.jam - Don't worry if you 
got far enough to somewhat parse the gcc-tools.jam file that one should 
be a cake walk.

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