Is it possible you built Clang in Debug? If you don't build a release version of Clang, everything is, indeed, very slow. I've made this mistake, and I think it's really easy to do. When I built boost 1.52.0 recently with a version of Clang very close to 3.2 it did not seem like it was building slowly to me. But I didn't compare the build speed with g++, so maybe I don't know what I'm talking about. On Tue, Dec 11, 2012 at 4:28 PM, Richard Hadsell

wrote:

I have been building the Boost libraries with g++ for many years. Someone recommended trying Clang, so I downloaded 1.52.0 and built it first with g++ 4.5.1 on Fedora 14. Then I started a build with clang 3.3, and it is taking forever. I have not made any measurements, but it must be at least an order of magnitude slower than g++. The math library seems to take the longest, but maybe there are other slow-building libraries yet to come.

Am I doing something wrong, or should I expect the clang build to be very slow?

In myuser-config I have this:

using clang : 3.3 : /directory_where_we_installed_**clang/bin/clang :<compileflags>"-fPIC"<**linkflags>"-fPIC" ;

The command line is this:

bin/bjam --user-config=myuser-config threading=multi instruction-set=core2 address-model=64 variant=release link=static,shared --stagedir=stageF14C clean

The clang version is: clang version 3.3 (trunk 169541) (llvm/trunk 169537) The OS is Linux Fedora 14.

-- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell@blueskystudios.com Blue Sky Studios http://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560

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