Sunday, 1 September 2013

Boost.Locale, ICU and Mingw

I've been doing a few small command-line programs, and needed to output text like this on a Windows terminal: "Opção inválida".

That led me to the Interesting World of Internationalization. Which is a lot more Interesting on Windows than on Linux, I must say. This should work, right?

UINT oldcodepage = GetConsoleOutputCP();
cout << "Olá\n" << endl;

In fact, not only did it not work reliably on all the Win7 machines I tried, but the endl wasn't outputted (hence, the "\n"). So, I've decided I needed something more powerful, like, say, ICU. And, fortunately, the size of the ICU DLLs would not be a problem.

Building ICU was easy. I just fired this on an msys terminal:

runConfigureICU MinGW --prefix=<DBG_PATH> --enable-debug --disable-release
make install

make clean

runConfigureICU MinGW --prefix=<REL_PATH> --disable-debug --enable-release
make install

No, I didn't bother with the recommended C++ changes, I'll look at it next time.

Next, building Boost. First thing was finding out what did I need to do to let Boost.Locale (and, as I found out later, also Boost.Regex) know that I had ICU available.

When invoking b2, I had to pass -sICU_PATH=<PATH_TO_ICU_HOME>. However, since I wanted to use different ICU versions for debug and release, that meant I couldn't just build Boost as I usually do, with --build-type=complete. Instead, I went for something like this:

    --build-dir=<BOOST_BUILD_DIR> toolset=gcc link=static,shared 
    runtime-link=shared threading=single,multi variant=debug 
    install > boost_install.log 2>&1

And I took a look at boost_install.log, as Boost started running its tests, including checking for ICU. And that was a good thing, because I spotted this early on:

- has_icu builds           : no

Boost was complaining about icui18n.dll and icudata.dll. And, sure enough, looking at my ICU lib folder, neither was anywhere to be found.

So, I went to Boost.Locale's (and Boost.Regex's) Jamfile.v2, looking for these dependencies. The first thing I noticed was that these dependencies didn't apply to MSVC. Actually, MSVC's dependencies included DLLs that I had on my system, so I renamed icui18n to icuin, and removed icudata. I also had to remove a couple of this_is_an_invalid_library_names, and finally I got this:

- has_icu builds           : yes

which made me quite happy. So, after Boost debug got built, I ran this little thingie to check that everything was OK:

#include "boost/locale.hpp"
using namespace boost::locale;

#include <algorithm>
using std::for_each;
#include <iostream>
using std::cout;
using std::endl;
#include <locale>
#include <string>
using std::string;

int main(int /*argc*/, char */*argv*/[])
    localization_backend_manager lbm = 
    auto s = lbm.get_all_backends();
    for_each(s.begin(), s.end(), [](string& x){ cout << x << endl; });

    generator gen;
    std::locale loc = gen("");
    cout << boost::locale::conv::between("Olá", "cp850", 
        std::use_facet<boost::locale::info>(loc).encoding()) << endl;

This outputted


This not only shows that Boost.Locale was built with ICU support (line 1), but also that the conversions are working (line 4).

Next: Testing this on a few machines.


  1. Can you tell exactly how you make boost locale work with icu? I'm totally in pain.

  2. Hi. It depends on the error. Where are you stuck?

  3. Just awesome, I've been struggling for a couple days trying to get Boost to detect ICU in Windows under Mingw32. Thanks!!! First bit of real help i could find on getting it to work.

  4. Thank you for the kind words, Michael, and for taking the time to comment. I'm glad my post was helpful. At the end of the day, that's why these posts exist.