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From: Ulrich Eckhardt (doomster_at_[hidden])
Date: 2006-03-29 03:06:36


Greetings!

I think it was with boost 1.30 where we started using the threads library and
at that time build support was not yet at the stage where we could really use
it the way we wanted it to so we mostly invented our own. The first thing we
did was to copy the required sourcefiles into the project where we needed
them, i.e. the most primitive form of static linking. Later on, we replaced
that with #including the sourcefiles (<lib/thread/src/...>) into a single
file - the same thing only done in a way that we could switch to the next
Boost version without changing our code. Well, at least we thought so, some
files moved between Boost versions inside the source folder, another problem
is that e.g. timeconv.inl provides things in an anonymous namespace and gets
included by more than one sourcefile but doesn't have include guards.

Anyhow, what I wonder is whether this is not a way that should be supported
actively. In our case, it significantly reduced the adoption barrier for the
threading lib, it also makes bjam use unnecessary (which I, even though I did
quite some things with it already, still find unwieldy and don't completely
understand), it avoids the problem of different compiler ABIs due to
different compiler versions or settings and it reduces the additional
required size of the final executable (example-prog[1] with above static
linking weighs 52kB, the thread lib alone would have been 92kB already
otherwise).

I personally would be interested in documenting how to use Boost libs this way
and also make it an officially supported way to do so.

cheers

Uli

[1]: The example program below has been compiled with GCC using Boost 1.33,
the only patch necessary was to add include guards to timeconv.inl.

#include <iostream>
#include <ostream>
#include <boost/thread/thread.hpp>
#include <boost/thread/xtime.hpp>

// for 'static' linking
#include <libs/thread/src/thread.cpp>
#include <libs/thread/src/xtime.cpp>
#include <libs/thread/src/mutex.cpp>
#include <libs/thread/src/exceptions.cpp>
#include <libs/thread/src/condition.cpp>

void thread()
{
    std::cout << "thread(): entering\n";

    boost::xtime tm;
    boost::xtime_get(&tm, boost::TIME_UTC);
    tm.sec += 2;
    boost::thread::sleep(tm);

    std::cout << "thread(): leaving\n";
}

int main()
{
    std::cout << "main(): creating thread\n";
    boost::thread th(&thread);
    std::cout << "main(): waiting\n";
    th.join();
    std::cout << "main(): done\n";
}


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