strange auto_link behaviour with --layout=system & defined BOOST_AUTO_LINK_NOMANGLE under vc9.0

[kopylov@…]

Env: Visual Studio 9.0.30729.1 SP Boost built with --layout=system

in user code:

#define BOOST_AUTO_LINK_NOMANGLE 1
#define BOOST_LIB_DIAGNOSTIC
#include <boost/filesystem.hpp>

in auto_link.hpp I made a little change in pragma message to clarify what happens:

#ifdef BOOST_AUTO_LINK_TAGGED
#  pragma commentcomment(lib, BOOST_LIB_PREFIX BOOST_STRINGIZE(BOOST_LIB_NAME) BOOST_LIB_THREAD_OPT BOOST_LIB_RT_OPT ".lib")
#  ifdef BOOST_LIB_DIAGNOSTIC
#     pragma message ("Linking to lib file(1): " BOOST_LIB_PREFIX BOOST_STRINGIZE(BOOST_LIB_NAME) "-" BOOST_LIB_TOOLSET BOOST_LIB_THREAD_OPT BOOST_LIB_RT_OPT "-" BOOST_LIB_VERSION ".lib")
#  endif
#elif defined(BOOST_AUTO_LINK_NOMANGLE)
#  pragma comment(lib, BOOST_STRINGIZE(BOOST_LIB_NAME) ".lib")
#  ifdef BOOST_LIB_DIAGNOSTIC
#     pragma message ("Linking to lib file(2): " BOOST_STRINGIZE(BOOST_LIB_NAME) ".lib")
#  endif
#else
#  pragma comment(lib, BOOST_LIB_PREFIX BOOST_STRINGIZE(BOOST_LIB_NAME) "-" BOOST_LIB_TOOLSET BOOST_LIB_THREAD_OPT BOOST_LIB_RT_OPT "-" BOOST_LIB_VERSION ".lib")
#  ifdef BOOST_LIB_DIAGNOSTIC
#     pragma message ("Linking to lib file(3): " BOOST_LIB_PREFIX BOOST_STRINGIZE(BOOST_LIB_NAME) "-" BOOST_LIB_TOOLSET BOOST_LIB_THREAD_OPT BOOST_LIB_RT_OPT "-" BOOST_LIB_VERSION ".lib")
#  endif
#endif

then I get the compiler output:

1>Linking to lib file(2): boost_filesystem.lib
1>Linking to lib file(3): libboost_system-vc90-mt-gd-1_44.lib

Looks like the "else" preprocessor section is executed.

[kopylov@…]

I see that auto_link.hpp is included 2 or more times, and BOOST_AUTO_LINK_NOMANGLE is undefined after first call. I wonder for what reason? Is it the possible solution to comment out #undef BOOST_AUTO_LINK_NOMANGLE ?

[John Maddock]

(In [66906]) Don't undef BOOST_AUTO_LINK_NOMANGLE. Refs #4902.

[John Maddock]

This is my mistake, BOOST_AUTO_LINK_NOMANGLE should not get #undef'ed by auto_link.hpp. Now fixed in Trunk.

John.