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bjam with mingw
by Angus Leeming 07 Sep '04

07 Sep '04

Please forgive the newbie questions, but I am trying and failing to build boost with MinGW. I've grabbed the CVS sources of boost from the sourceforge anonymous mirror. I've installed MinGW and MinSYS. The MinGW tools are in my path. From the MinSYS console: $ cd ~/boostcvs $ which which c++ /mingw/bin/c++ $ c++ --version c++.exe (GCC) 3.2.3 (mingw special 20030504-1) Just to check that the tools are working: $ cd libs/spirit/phoenix/test $ c++ -I$HOME/boostcvs -o new_test new_test.cpp $ ./new_test /////////////////////////////////////////////////////////////////////////////// Tests concluded SUCCESS!!! /////////////////////////////////////////////////////////////////////////////// Now trying to do something similar using bjam: $ cd ~/boostcvs/libs/test/build $ bjam '-sTOOLS=mgw' CALL "C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\bin\VCVARS32.BAT" >nul "C:\Program Files\Microsoft Visual Studio .NET 2003\VC7\bin\cl" /Zm800 -nologo /EHsc -c -DBOOST_TEST_NO_AUTO_LINK=1 /Z7 /Od /Ob0 /EHsc /GR /MTd /Op /Zc:forScope /Zc:wchar_t -I"..\..\..\bin\boost\libs\test\build" -I"d:\MinSYS\1.0\home\Angus\boost_cvs" -Fo"..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\unit_test_main.obj" -Tp"d:\MinSYS\1.0\home\Angus\boost_cvs\libs\test\build\../src/unit_test_main.cpp" ...failed vc-C++ ..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\unit_test_main.obj... vc-C++ ..\..\..\bin\boost\libs\test\build\libboost_unit_test_framework.lib\vc7.1\debug\runtime-link-static\threading-multi\supplied_log_formatters.obj The system cannot find the path specified. The system cannot find the path specified. [ snip all other, similar messages ] For the life of me I can't see why bjam is trying to build the VC++ target. I can't even run $ bjam --help because it just does the same thing, trying and failing to build stuff with VC++. I have also tried running from the top level boost directory and with the '-sMINGW_ROOT_DIRECTORY=/d/mingw' command line option to bjam, all to no avail. (From my understanding of the docs at http://www.boost.org/tools/build/v1/mingw-tools.html, that shouldn't be necessary.) I have changed the TOOLS name to 'mingw' rather than 'mgw'. Again , no dice. Finally, in desperation, opening up a DOS prompt and repeating the exercise. Nope. Same result. Can anyone help me out? Regards, Angus

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RE: [Boost-users] output stream cloning?
by Ben Hutchings 07 Sep '04

07 Sep '04

Jon Biggar <jon(a)levanta.com> wrote: > Is there any package in Boost (or upcoming in the Boost review queue) > that would let me create an output stream that clones its output to > one or more underlying output streams? Jonathan Turkanis's Iostream library, which is currently under review and has been mostly positively received, seems to make it pretty trivial to write such a thing - see <http://lists.boost.org/MailArchives/boost/msg69799.php> and <http://lists.boost.org/MailArchives/boost/msg69827.php>.

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problem with CVS Boost.Python with MSVC
by Stephen D Evans 07 Sep '04

07 Sep '04

The CVS change to boost/boost/python/detail/prefix.hpp from revision 1.3 to 1.4 has obviated the effect of boost/boost/python/detail/wrap_python.hpp in _DEBUG when compiling with MSVC. Python now forces the debug library as if BOOST_DEBUG_PYTHON is permanently in effect. Revision 1.3 does not exhibit this problem. The added #include <pyconfig.h> is the cause. Stephen D Evans

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dangerous use of boost::bind
by Gast 128 07 Sep '04

07 Sep '04

Dear all, In my work I use the boost libraries quite frequently, especially boost::bind to create function objects. However its use is not as transparent as I hoped for. Especially using functions in boost bind with signatures returning const& can give unpredictable results. For example: struct KX { KX (int i); //etc. }; typedef std::pair<int, KX> pair_t; pair_t do_kx_pair(int i) { return std::make_pair(i, KX(i)); } //following will go wrong: KX x = boost::bind(&pair_t::second, boost::bind(&do_kx_pair, i))(); The last line compiles on Visual .NET 2003 without any warning (even on level 4). However after spending two days in boost bind source code, I could see that it actually returns const& to a temporary created by boost bind. The reason for this is that arguments are copied by value, and thus functions with const & (or in this case pointer to member) can return then const & from temporaries. Is there no way that at least boost::bind could issue a compiler warning? Because now I have to think deep before I create a nested boost bind construction. For example the following construction is not wrong; the const & is again taken from a temporary which boost::bind holds, but this is destroyed after the expression: KX x = boost::bind(&pair_t::second, do_kx_pair(i))(); If this is not solvable, perhaps it's a good idea to include this case in the documentation. Wkr, me (btw boost::bind is a great improvement over the std::mem_fun and std::bind1st etc.)

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Problems with boost::format and Visual C++ 7.0
by Tom Quarendon 07 Sep '04

07 Sep '04

I have trouble compiling code that makes use of the boost::format library. In particular I get compile errors from basic_format::operator= method (line 90 format_implementation.hpp). If I change the body to look like if(this == &x) return *this; basic_format<Ch, Tr> x1(x); // These 2 lines used x1.swap(*this); // to be 1 return *this; It compiles. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.737 / Virus Database: 491 - Release Date: 11/08/2004

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output stream cloning?
by Jon Biggar 07 Sep '04

07 Sep '04

Is there any package in Boost (or upcoming in the Boost review queue) that would let me create an output stream that clones its output to one or more underlying output streams? -- Jon Biggar Levanta Inc jon(a)levanta.com

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Directory_Iterator causes MFC App to Freeze
by RYAN ROSARIO 06 Sep '04

06 Sep '04

Hi, I am writing an MFC program in MSVC7 that must pass a path from one dialog box to another upon pressing a button. I attempt to pass the path to the next dialog by using a directory iterator: fs::directory_iterator startIt(scanPath); (***) where scanPath is an object of type path. PICtoolProgressWnd temp(this,startIt); I pass the iterator into the constructor for the second dialog. When I attempt to run this program, my program just hangs after clicking the button and I cannot exit it. The second dialog never appears. The only way out is to Alt-Ctrl-Delete out of the program. The only other clue given is that when the program freezes, the "xstring" file opens with a green arrow pointing at what appears to be a definition of operator= or something of that sort. I have commented out practically all of my code in the button click event handler and determined that when the iterator is declared, (***) above, the program freezes. When this line is commented out, the program responds. What could I be doing wrong?? Below is some more code: //Creating the dialog if ( temp.DoModal() == IDOK) { //Display results. } else { //Are you sure you wish to cancel this process? } //Second dialog constructor. PICtoolProgressWnd::PICtoolProgressWnd(CWnd* pParent /*=NULL*/, fs::directory_iterator start) : CDialog(PICtoolProgressWnd::IDD, pParent) { startScanPath = start; } //startScanPath is a member variable of type fs::directory_iterator. Your help is greatly appreciated. Thanks in Advance, Ryan --------------------------------- Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard.

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Using MPL to write is_derived_from_std_basic_ostream
by Angus Leeming 06 Sep '04

06 Sep '04

I'm trying to ascertain whether a given class is, or is derived from, std::basic_ostream, but I've ground to a halt. The attached code successfully reports those classes that do derive from std::basic_ostream but fails to compile when I test std::string, bool, char etc. I can see what is going wrong, but have run out of ideas about how to fix it. I'm also painfully aware that my attempts are just plain ugly. Can someone show me the way forward? Regards, Angus

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global stream manipulators for the format library
by Justin Findlay 05 Sep '04

05 Sep '04

I've got some code that uses the format library to format output, not out of necessity, but rather out of a wanton enjoyment derived from using the syntax, having lately (relatively) discovered boost, prefering the boost::format simple syntax to the posix printf and std::ostringstream flavored solutions. The "problem" I have is that for the output of every double, I have to specify the precision: int main() { cout << setprecision(18); cout << format("Bunner p' air: %1% torr\t\tN$_2$: %2% torr\n" " C air: %3%\t\tN$_2$: %4%") % group(setprecision(18), bunner::air::pp_av) % group(setprecision(18), bunner::N2::pp_av) % group(setprecision(18), bunner::air::c_av) % group(setprecision(18), bunner::N2::c_av) << endl; //... return 0; } Is there a graceful solution, or am I using this library beyond what it was intended for? Something like the following naturally suggests itself, but I don't think it is standard compliant: the constructor doesn't seem to like using a static object, actually the linker couldn't find the 'prmanip' object. class Fmt { public: Fmt() { cout << "duh" << endl << prmanip << constants::pi << endl; } static std::_Setprecision setpr(const int&pr) { prmanip = std::setprecision(pr); return std::setprecision(pr); } static std::_Setprecision prmanip; }; int main() { cout << setprecision(18); Fmt::setpr(18); //... Justin

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Problem using Boost Signals HPP file
by Brian Braatz 05 Sep '04

05 Sep '04

I am using vc7.1 MS Visual Studio 2003. I have tried using the boost signals (boost/signal.hpp) library in both my application and a Visual Stuido project file using the signal_test.cpp file. (made a blank C++ win32 console app project file- and then added the include dir for boost- I did nothing else). in either case I get: Compiling... signal_test.cpp Linking... LINK : fatal error LNK1104: cannot open file 'libboost_signals-vc71-sgd-1_31.lib' Build log was saved at file://c:\Rmtg\Root\_Common\_Lib\Boost\V_1_31\libs\signals\test\signal_test\signal_test\Debug\BuildLog.htm signal_test - 1 error(s), 0 warning(s) ---------------------- Done ---------------------- Build: 0 succeeded, 1 failed, 0 skipped My project file is quite bare other than pointing to boost as an include dir. I am perplexed on how visual studio is even AWARE of the lib name (since I did not tell it). On the machine I am using, I have not built boost static or dll libs. That would solve my problem, but not completely as what I *need* to do is use the hpp and *not* link to the lib. My questions: has anyone run into this before? Is Boost::signals supposed to work by just being able to #include the hpp? Any thoughts here? (one of those situations where I am really scratching my head). **ANY** thoughts or suggestions greatly appreciated

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