February 2010 - Boost-users

Re: [Boost-users] [boost.asio] Flush serial port buffers?
by Pascal Kesseli 01 Feb '10

01 Feb '10

No ideas on this one? > Hi everyone > > My program currently writes some characters to a > device connected over the serial interface and > subsequently changes the baud rate, followed by > sending some more characters. > > The problem is that the first transfer does not > seem to complete before the baud rate switch and > thus is sent with the new baud rate, which is not > supposed to happen. What I am looking for is > something like a flush() before changing the baud > rate. Using: > > boost::asio::write(*port, buffer(buf, size), transfer_all()); > > does not seem to work. Any suggestions? > > Thanks and best regards > Pascal

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Mingw: build, install, .LIB files and boost-config?
by John Pye 01 Feb '10

01 Feb '10

Hi all While I'm aware that MinGW is not one of the 'primary' platforms for MinGW, I wanted to ask a few questions to help me in the task of building a binary copy of Boost for this platform that's as good as it can be. Firstly, what would be the correct build commands to build Boost for MinGW such that I end up with both shared libraries and static libraries? What I've worked out so far is shown here: http://ascendwiki.cheme.cmu.edu/Binary_installer_for_Boost_on_MinGW Secondly, to install Boost at an arbitrary path under MinGW, what is the correct BJAM command? On MinGW, I'm not running ./configure, so the suggestions from the Unix build documentation don't make sense. By default under MinGW, if I run "bjam install", my files end up in c:\Boost but I'd like too have another target directory, so that it's possible to build even without write privileges to that folder. Is there such a thing as "bjam --install-prefix=c:/MinGW install"? Is there a way to strip out all the redundant folder levels like "release" and "gcc-mingw-3.4.5" etc? Third, using BJAM on MinGW results in .LIB files being generated. These .LIB files are NOT correctly names for use with MinGW. As far as I can tell, I have to rename them as .A files, or else do something else with them so that they'll correctly be detected by the the GCC "-l" linker flag. Finally, there was a bit of discussion on the mailing list about a year ago about providing a "boost-config" script. With the ever-changing naming conventions for Boost libs, and the possible presence of static libraries, shared libraries, -mt, -d, and other file suffixes, such a script would be INVALUABLE for people looking to access pre-built Boost binaries for their projects. It would be an almost trivial task to implement such a script -- has there been any progress on this anywhere? Can I suggest that for MinGW, a native shell script, with file paths constructed relative to the boost-config path, would probably be the best way, rather than pkg-config, which is not available in MinGW/MSYS by default. Feel free to direct me to the online documentation of this stuff if it exists -- I couldn't find it though. Cheers JP -- John Pye Dept of Engineering Australian National University http://pye.dyndns.org/

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boost serialization stream error question
by Gabe Sibley 31 Jan '10

31 Jan '10

Dear All, I'm using boost serialization and have come across issues with "steam error" when I try to deseriailze from an xml or text archive. Binary archives are fine, but I can't use binary because my users need xml archives. The problem is caused by double values less than DBL_MIN. Apparently, streaming such values in causes the input stream fail_bit to be set, which causes the serialization lib to throw an exception. One work around is to make sure all double values are clamped and finite when the archive is created. I can live with this, esp. since I have algorithms that will from time to time produce non-finite results. So far what I've done is just replace BOOST_SERIALIZATION_NVP macro with the following MAKE_NVP macro that calls "FixReal": #define BOOST_SERIALIZATION_NVP(name) \ boost::serialization::make_nvp(BOOST_PP_STRINGIZE(name), name ) // Use this macro instead of BOOST_SERIALIZATION_NVP because it fixes doubles that are not streamable. // That is, it fixes double values that cause streaming errors. #define MAKE_NVP(name) \ boost::serialization::make_nvp(BOOST_PP_STRINGIZE(name), FixReal(name) ) // note the call to FixReal // does nothing -- just pass all non-double types through template<class T> inline T& FixReal( T& t ) { return t; } /// Routine to make sure doubles are streamable -- Nan, Inf, etc. cause stream errors, so we prevent them. inline double& FixReal( double& d ) { if( d < DBL_MIN ) { d = DBL_MIN; } if( d > DBL_MAX ) { d = DBL_MAX; } if( std::isnan(d) ) { d = 0; } if( std::isinf(d) ){ d = DBL_MAX; } return d; } /// We also need to fix double arrays. The ugly syntax is because // we have to pass and return a reference to an array. inline double (&FixReal( double (&d)[2] ))[2] { for( size_t ii = 0; ii < 2; ii++ ){ FixReal(d[ii]); } return d; } Ok, here's my question: How can I get the "FixReal" functionality above without having to write a specialized function for every possible double signature? For instance, I don't want to have to write inline double (&FixReal( double (&d)[3] ))[3] inline double (&FixReal( double (&d)[4] ))[4] ... etc. or any of the other POD double signatures possible. I just want the serialization library to fix the errant double values when I create the archive. I guess I could modify the "void save(const double t)" function in basic_text_oprimitive.hpp to check all doubles, but that seems like a bad plan. Any suggestions? thanks for your help, Gabe

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Strange output from boost::exception diagnostic_information
by pholding 31 Jan '10

31 Jan '10

-------------------------------------------------------------------------------- I've been having a look at the diagnostic_information function in the boost exception library, but seem to be getting a strangely formatted output. The code I'm using is as follows Code: #include <boost/exception/diagnostic_information.hpp> #include <stdexcept> #include <iostream> void myerror(){ throw boost::enable_error_info(std::range_error("blah")); } int main(){ try{ myerror(); } catch(boost::exception & e){ std::cerr << diagnostic_information(e) << std::endl; } return 0; }The output is as follows: Quote: Throw in function (unknown) Dynamic exception type: N5boost16exception_detail19error_info_injectorISt1 1range_errorEE std::exception::what: blah What I don't understand is why I'm getting N5, 16, 19, ISt11 and EE between the details of the exception type. To rule out my code, I compiled the example_io.cpp file provided in the boost example documentation and I'm getting a similar output. Does anyone what is causing the strange characters displayed? I'm running Ubuntu 9.10 and the version of g++ is 4.4.1 -- View this message in context: http://old.nabble.com/Strange-output-from-boost%3A%3Aexception-diagnostic_i… Sent from the Boost - Users mailing list archive at Nabble.com.

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