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A boost::python problem
by lxcypp lxc 05 Aug '08

05 Aug '08

*I abstract the problem below:* t1.cpp: #include <boost/python.hpp> #include <boost/enable_shared_from_this.hpp> #include <boost/shared_ptr.hpp> #include <iostream> #include <string> #include <list> using namespace std; using namespace boost::python; static object mainobj, global; class A : public boost::enable_shared_from_this<A> { public: void test(); }; class X { public: void test(boost::shared_ptr<A> pObj){} }; typedef boost::shared_ptr < A > A_ptr; typedef boost::shared_ptr < X > X_ptr; X_ptr xx; void A::test() { object aa = global[ "aa" ]; A_ptr pa( shared_from_this() ); aa( xx, pa ); } BOOST_PYTHON_MODULE(pythonobject) { class_ <A>("A") .def("test", &A::test) ; class_ <X>("X") .def("test", &X::test) ; register_ptr_to_python <A_ptr>(); register_ptr_to_python <X_ptr>(); } int main() { Py_Initialize(); initpythonobject(); PyRun_SimpleString("import pythonobject"); mainobj = import("__main__"); global=(mainobj.attr("__dict__")); A_ptr a( new A ); X_ptr x( new X ); xx = x; try { exec_file("t1.py", global, global); a->test(); a->test(); a->test(); } catch (error_already_set) { PyErr_Print(); } return 0; } t1.py: #!/usr/bin/python #coding:utf-8 def aa(x,a): x.test( a ) return 1 *after execute t1.cpp , I got this erro info: terminate called after throwing an instance of 'boost::bad_weak_ptr' what(): tr1::bad_weak_ptr When debug the program, I found after first "a->test()" call, a._internal_weak_this.use_count became 0. It's obviously wrong... so the after "a->test()" will cause error. But if change void test(boost::shared_ptr<A> pObj){} to void test(A* pObj){} I got no error. The errror is gone. Will someone explain this prolbem to me? Thank you.*

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MS SDK 2003 Compiler Configuration
by bob＠jerand.com 05 Aug '08

05 Aug '08

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Cross-compiling Boost 1.35.0
by Grant Erickson 05 Aug '08

05 Aug '08

I have been attempting to generate a build environment for boost in which two targets are involved: 1) Native GCC (Whatever the host build system is) 2) DENX ELDK 4.1 (PowerPC 4xx / Linux) With the assumption that (1) and (2) are both GCC-based, I have (1) working well enough. However, the information at: http://lists.boost.org/boost-users/2007/01/24400.php Seems stale for 1.35.0 in that GCC_ROOT_DIRECTORY, GCC and GXX are no longer referenced. My general recipe in my top-level "glue" makefile is as follows, with commands to extract the source, build a link farm, build any objects and install the library: BoostArchive = boost_1_35_0.tar.gz BoostSource = boost_1_35_0 BoostConfigure = $(BuildDirectory)/configure BoostMakefile = $(BuildDirectory)/Makefile BoostUserConfig = $(BuildDirectory)/user-config.jam BoostLibraries = filesystem \ thread BoostLibrariesList = $(subst $(SPACE),$(COMMA),$(strip $(BoostLibraries))) $(BoostSource): $(BoostArchive) tar -zxvf $< $(BoostConfigure): | $(BoostSource) lndir -silent $(CURDIR)/$(BoostSource) $(BuildDirectory) $(BoostMakefile) $(BoostUserConfig): $(BoostConfigure) cd $(BuildDirectory) && \ BJAM_CONFIG="" \ $(BoostConfigure) \ --prefix=$(ResultDirectory) \ --with-toolset=gcc \ --without-icu \ --with-libraries=$(BoostLibrariesList) build: $(BoostMakefile) unset MAKEFLAGS && \ $(MAKE) -C $(BuildDirectory) \ BJAM_CONFIG="" \ all install: unset MAKEFLAGS && \ $(MAKE) -C $(BuildDirectory) \ BJAM_CONFIG="" \ install My suspicion is that there's some new 1.35.0-specific magic to pass via BJAM_CONFIG that allows me to specify the GCC and G++ executables (and longer-term, the OS since that might be cross-compiled too rather than Linux in both cases). Any insights on what that new magic might be? Regards, Grant

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[asio] using with mdns/dns-sd?
by Isaac Dupree 05 Aug '08

05 Aug '08

What I want: a (open-source, OS-portable) way to advertise my game on a local LAN, so local players can play with each other easily ("Zeroconf networking"). It looks like MDNS/DNS-SD is the most sensible choice; but it needs (or greatly benefits from) interfacing with whatever the system is running (e.g. Avahi on Linux, and I guess Bonjour on Mac, and I'm not sure quite how people manage to use it on Windows). My current networking is based on Boost.Asio, which I'm pretty happy with as a socket library (yay! finally learning how to use sockets!). Does this MDNS/DNS-SD need support from Boost.Asio, or else what's a good way to go about using it? Maybe to use Bonjour's interface because Avahi apparently implements a compatibility layer for that? (P.S. Although the actually-asynchronous IO was a little confusing. With my Haskell background, I eventually realized that many of the examples were highly obfuscated versions of lambda functions (continuations) defined within other functions, because C++ doesn't yet support such things.) -Isaac

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Website not up to date?
by Klaim 05 Aug '08

05 Aug '08

Hello, i notice that the boost.org website main page doesn't display any announcement or any other news since few months last news is : - Egg review result ><http://comments.gmane.org/gmane.comp.lib.boost.announce/193>May 18th, 2008 02:59 GMT In the mailing lists (boost-users and boost) i see some review announcements and that the v1.36 is in beta. But It's not displayed on the website. Is this a bug or is it volunteer? Joël Lamotte.

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[boost-users][multi-index] subtracting containers
by Igor R 04 Aug '08

04 Aug '08

Hi, What would be the shortest way to subtract 2 containers? multi_index_container < // ordered key > cont1, cont2; cont1.insert(a); cont1.insert(b); cont1.insert(c); cont2.insert(b); // here I'd like to do cont1 -= cont2, so that cont1 would contain (a,c) Obviously, the operator -() or -=() is unsupported. So is there a way to do this without an explicit loop? IIUC, std::remove_if() wouldn't work here, because it tries to rearrange the elements... Thank you!

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boost::serialization size limit??
by Campbell Morrison 04 Aug '08

04 Aug '08

Hi, I am using boost::serialization to send and recieve some objects over a socket (as per Asio - Serialization Example). I find that when I make the objects contain very large std::vectors (i.e. KB to MB), I get stream errors when recieving the object. Is there an upper limit in size in the serialization? Or could it be an stl or Asio thing? The type in the object that is causing the trouble is a: std::vector< double >. I haven't tried with other types. regards, campbell.

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!BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x564) ) causing problems on MSVC compiler
by Terdale, Shantibhushan 04 Aug '08

04 Aug '08

I am using boost for the first time and not much aware of whets going on. I am including serialization archive hpps and it is including these lines eventually somewhere inside namespace detail{ #if !BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x564) ) using namespace boost::detail; #endif I am using Visual Studio and MSVC compiler and this using directive is causing me problems. There is a CRITICAL_SECTION defined in boos::detail which conflicts with standard windows CRITICAL_SECTION. The thing am not able to understand is how is this Workaround works ? If this workaround checks for BORLANDC then shouldn't it just place that code for Borland compiler? Please help. Is there any other macro I can define or undefine that will get rid of this. Thanks Shanti

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[boost-users] Can't build Boost library, help please
by Hermann 04 Aug '08

04 Aug '08

I'm sorry if this wasn't posted using proper tagging the first time. I want to use Boost.Serialization so I need to build the library. But when I follow the steps in here http://www.boost.org/doc/libs/1_35_0/more/getting_started/unix-variants.html (section 5.1) I get the following error upon issuing the ./configure command: Building Boost.Jam with toolset gcc... ./configure: line 199: ./bootstrap/jam0: No such file or directory I'm using gcc version 3.4.3 20041212 (Red Hat 3.4.3-9.EL4) What could be the problem? Thanks in advance.

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[Serialization] A few questions about boost::serialization
by Sebastian.Karlsson＠mmorpgs.org 04 Aug '08

04 Aug '08

Hi, I'm considering using boost::serialization but have a few questions which I would love to get answered. 1) In the overview section performance is nowhere to be seen as a goal, which for my use case is very important. If I were to use the binary archive, how well would it perform in comparsion to a hand crafted optimized serialization aproach? I've seen in the examples that strings seems to be used to identify data, won't this create a large overhead for both deserilzation and storage? 2) I saw the thread about the reason for boost::any not being serializable. But I don't really care about portability, so in that case, is it possible to implement a non intrusive serialization aproach to boost::any? Would really appreciate some little snippet for that if that is the case. If that's not possible my last option would naturally be to make an intrusive implementation, I see no obvious aproach here since I can't make a virtual template function, so I'm kind of hoping someone could push me in the right direction if it comes to this. Besides this I can only say that the library have a very slick interface and I really dig the design :) // Sebastian Karlsson

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