[boost] [Test] boost_unit_test_framework and main()

From: Douglas Gregor (doug.gregor_at_[hidden])
Date: 2007-05-15 02:07:49

I'm having trouble getting programs using boost_unit_test_framework  
to link. The fundamental issue is that trying to link something like  
this:

        g++ -fPIC -o algorithms_test algorithms_test.o - 
lboost_unit_test_framework

dies with a linker error:

   /usr/bin/ld: Undefined symbols:
   _main
   collect2: ld returned 1 exit status

The issue, of course, is that "main" lives within the library  
boost_unit_test_framework, but linkers don't look into libraries  
(either static or dynamic) to find main. I suspect this is also the  
reason for the FAQ item on the test library page (http:// 
www.boost.org/libs/test/doc/faq.html#Item_9), which says that Boost  
Test components cannot be compiled as DLL, but perhaps there are  
other issues there.

Our tests pass because BBv2 decides to put the archive file on the  
link line:

        g++ -fPIC -o algorithms_test algorithms_test.o  
libboost_unit_test_framework.a

For some reason, this non-standard practice seems to work... but I  
can't imagine it's truly portable, and it forces users of  
boost_unit_test_framework into statically linking in a non- 
traditional way.

Why must main() be in a library? It seems a trivial matter to fix.

        - Doug