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[iostreams] Error-handling with filters
by Paul Giaccone 23 Jan '06

23 Jan '06

How can you deal with a corrupt file when using filters? I have a chain of filters that includes a bzip2 and multichar filter have written myself. If the read() function fails to find what it expects in the file, it returns 0 (meaning "no characters read"). Otherwise it returns the number of characters read (which should be equal to the number of characters requested in the third function parameter) or -1 if the end of the file is reached. This works fine if the file is as is required, but if it is corrupted in any way, the program either hangs or crashes at if (s->strm != strm) return BZ_PARAM_ERROR; in bzlib.c, with s as a pointer that cannot be read (set to 0xcdcdcdcd). I'm working in Microsoft Visual C++ and gcc 3.2.3. How should this be handled? I haven't seen anything about it in the documentation. I imagine I should throw an exception instead of returning 0 (perhaps an iostreams exception?). Given that the crash is the bzip2 (bzip2 being the first operation done when deserialising the file), where would I put the associated catch block? Thanks, Paul

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[Boost.Build v2] Incorrectly handled header dependencies
by Jaroslav Gresula 23 Jan '06

23 Jan '06

I'm using the CVS version of Boost.Build on WinXP. Consider the following project: top/ | +-- include/ | | | +-- dir/ | | | +--header.h +-- Jamroot +-- main.cxx // -- main.cxx #include <dir/header.h> int main() { return 0; } # -- Jamroot path-constant TOP : . ; exe app : main.cxx : <include>$(TOP)/include ; Modification of header.h does not invoke the app target. I'm not familiar with bjam at all, but there is one thing I noticed and which might be relevant. When bjam is run with -d7 the include directory appears in the bjam's output with leading '/' and 'header.h' itself is labeled as missing: set SEARCH = /c:/Temp/bb2/include set HDRSCAN = #[ t]*include[ ]*(<(.*)>|"(.*)") set SCANNER = object(c-scanner)@45 set HDRRULE = scanner.hdrrule set HDRGRIST = object(c-scanner)@45 build file: root = '/c:/Temp/bb2/include' dir = 'dir' base = 'header' search <object(c-scanner)@45>dir/header.h: /c:/Temp/bb2/include\dir/header.h build file: dir = '\c:\temp\bb2\include\dir' build file: dir = 'dir' base = 'header' search <object(c-scanner)@45>dir/header.h: dir/header.h build file: dir = 'dir' set SEARCH = set HDRSCAN = set SCANNER = set HDRRULE = set HDRGRIST = bind -- <object(c-scanner)@45>dir/header.h: dir/header.h time -- <object(c-scanner)@45>dir/header.h: missing made stable <object(c-scanner)@45>dir/header.h made* newer <p.-object(c-scanner)@45>main.cxx made+ update <pbin\msvc\debug>main.obj made+ update <pbin\msvc\debug>app.exe made update all -- Jarda

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Hello: boost::filesystem with cygwin - windows style paths
by Simon Lam 22 Jan '06

22 Jan '06

Hello all, I've been fiddling around with the gnu gcc programming enviroment on cygwin, trying to make boost::filesystem work. I've hit a snag where the boost libraries consider my filesystem to be single rooted, and thus path won't take "c:\" as an argument. I've compiled the simple_ls.cpp program included in the documentation. It uses boost::filesystem::path::native_file_string(), and this returns a unix style path. I've tried running "simple_ls c:" but it complains that /home/<path to current dir>/c: is unavailable. I want to be able to use this in a program thats for windows, but independent of cygwin. Any ideas how to work around this? >Thanks >Simon (ps: yah! my first post!)

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[Boost.Build v2] how to disable specific warnings on gcc
by Jaroslav Gresula 22 Jan '06

22 Jan '06

If I want to disable a specific warning on gcc (3.4.2, mingw) and use -Wall at the same time then on the gcc commnad line the -Wall option must precede the option disabling the specific warning. E.g. gcc -Wno-non-virtual-dtor -Wall main.cxx ignores the '-Wno-non-virtual-dtor' option, whereas gcc -Wall -Wno-non-virtual-dtor main.cxx works as expected. My problem is that I can't achieve the correct option order with Boost.Build v2 as the -Wall is used by default and the disabling option is always put before it. I tried to specify it in the toolset configuration: using gcc : : : <cxxflags>-Wno-non-virtual-dtor ; and also putting <toolset>gcc:<cxxflags>-Wno-non-virtual-dtor ; into project's requirements but neither works. Please, could anyone help me out with this? -- Jarda

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glibc detected malloc(): memory corruption:
by Daniel Weiss 22 Jan '06

22 Jan '06

Hi I am working with the matrix libraries (#include "boost/numeric/ublas/matrix.hpp" etc...) and my program is running fine during several loops but suddenly stops, showing the message: *** glibc detected *** malloc(): memory corruption: 0x0865e638 *** /bin/sh: line 1: 8311 Aborted I found that the error occurs on the line where I initialize some matrices: matrix<float_type> Stiff_matrix(6,6), Qq_matrix(3,3); What I don't understand is, that the program runs through this line the first 3 times and only the 4th time the error occurs.... How can that be?? Greets, Dan. -- 10 GB Mailbox, 100 FreeSMS/Monat http://www.gmx.net/de/go/topmail +++ GMX - die erste Adresse für Mail, Message, More +++

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[Win32 VC70 Linking] Hard coding library name for the final linking ('libboost_filesystem-vc7-mt-s-1_33_1.lib' ...)?
by Allen Zhao 22 Jan '06

22 Jan '06

Hi, All, I have a weired problem in linking libtorrent dll with my application. The libtorrent depends on 3 boost projects. This is what I got: test fatal error LNK1104: cannot open file 'libboost_filesystem-vc7-mt-s-1_33_1.lib' It looks like I have to build libboost_filesystem-vc7-mt-s-1_33_1.lib, and add this library explicitly in the final linking, no mater what my project setting is. The library filename must be named above. I also built a VC 7.0 from scratch (which contains all the needed boost source (not the prebuilt library)), it all ends the same linker error. Mystereous as it is, I am a little suspecious now. Is it possible that this library name is actually coded somewhere by some algorithm? Best regards, Allen Zhao

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Re: [Boost-users] [tuple] no easy access to get function
by JOAQUIN LOPEZ MU?Z 22 Jan '06

22 Jan '06

----- Mensaje original ----- De: Frank Birbacher <bloodymir.crap(a)gmx.net> Fecha: Sábado, Enero 21, 2006 2:29 am Asunto: [Boost-users] [tuple] no easy access to get function > Hi! > > Today I wanted to std::transform a range of tuples into a sequence of > one element. I thought I could just take the address of some > tuple::get<N> function. Maybe also specify the Tuple type as template > parameter [...] > I'd rather want to take the address of boost::tuple::get<N,Tuple>, but > the template parameters won't match. > Maybe you forgot the final s in "tuples" when writing boost::tuples::get<N,Tuple> ?? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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statechart: interaction with environment
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, I try to understand how boost::statechart work - so I have some questions. If the FSM implements a communication protocol how does the FSM interact with the environment? 1. Problem: How to passing callback-functions to the FSM? * The callback should be invoked if the FSM is in a certain state and some conditions are met. * Do I have to pass the callback(s) with an event which has to be injected to the FSM from outside and store them in a given state? 2. Problem: How to pass initialization parameter into the FSM? * Some states need to be initialized with parameters (for instance host and port in order to create a socket). * Do I Have to pass the parameters via injected events? 3. Problem: How to pass data between several states in an FSM? * Same as Problem 2? With best regards, Oliver

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statechart: howto connection two different FSMs
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, The tutorial of boost::statechart contains an incomplete example of connecting two FSMs of the same type. For me it is not clear how the events are propagated between this two FSMs (concret C++-code) and if its possible to connect two FSMs of different type! Could you give me a simple (complete) example, please? Regards, Oliver

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statechart: unable to compile examples - additional compiler flags needed?
by Oliver.Kowalke＠infineon.com 21 Jan '06

21 Jan '06

Hello, I'm using statechart on LINUX with gcc-3.4.2. bjam was able to compile the examples but if I copy the StopWatch-example into a Kdevelop-project I get errors?! I assume I've to put some additional compiler-flags which are not mentioned in the tutorial. Could you help please! In file included from /opt/boost/include/boost-1_33_1/boost/statechart/simple_state.hpp:13, from /opt/boost/include/boost-1_33_1/boost/intrusive_ptr.hpp:35, from /opt/boost/include/boost-1_33_1/boost/statechart/detail/state_base.hpp:1 6, from /opt/boost/include/boost-1_33_1/boost/statechart/state_machine.hpp:16, from /opt/boost/include/boost-1_33_1/boost/intrusive_ptr.hpp:34, from /opt/boost/include/boost-1_33_1/boost/statechart/event_base.hpp:15, from /opt/boost/include/boost-1_33_1/boost/statechart/event.hpp:11, from /home/kowalke/Projects/tcpproto/src/tcpproto.cpp:33: /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: Fehler beim Parsen before `<' token /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:3 6: Fehler: destructors must be member functions /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp: In function `void boost::statechart::detail::leaf_state()': /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:3 6: Fehler: ` void boost::statechart::detail::leaf_state()' redeclared as different kind of symbol /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: previous declaration of `template<class Allocator, class RttiPolicy> class boost::statechart::detail::leaf_state' /opt/boost/include/boost-1_33_1/boost/statechart/detail/leaf_state.hpp:2 6: Fehler: previous non-function declaration `template<class Allocator, class RttiPolicy> class boost::statechart::detail::leaf_state' ... with best regards, Oliver

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