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Re: [Boost-users] [shared_ptr] Is it possible for a shared_ptr to
by Max 29 Dec '08

29 Dec '08

There seems to be a solution that can make the code a little bit cleaner and easier to maintain. #define DECLARE_PTR_AUTO_DELETOR(CLASS, VAR_PTR)\ boost::scoped_ptr<CLASS> auto__deletor__for__ ## VAR_PTR (VAR_PTR) AcDbCircle *pFace =new AcDbCircle (AcGePoint3d::kOrigin, AcGeVector3d::kZAxis, 1.0) ; AcDbCircle *pLeftEye =new AcDbCircle (AcGePoint3d (0.33, 0.25, 0.0), AcGeVector3d::kZAxis, 0.1) ; AcDbCircle *pRightEye =new AcDbCircle (AcGePoint3d (-0.33, 0.25, 0.0), AcGeVector3d::kZAxis, 0.1) ; AcDbArc *pMouth =new AcDbArc (AcGePoint3d (0, 0.5, 0), 1.0, 3.141592 + (3.141592 * 0.3), 3.141592 + (3.141592 * 0.7)) ; DECLARE_PTR_AUTO_DELETOR(AcDbCircle, pFace); DECLARE_PTR_AUTO_DELETOR(AcDbCirclep, LeftEye); DECLARE_PTR_AUTO_DELETOR(AcDbCircle, pRightEye); DECLARE_PTR_AUTO_DELETOR(AcDbArc, pMouth); // Set the color property. pFace->setColorIndex (2) ; pLeftEye->setColorIndex (5) ; pRightEye->setColorIndex (5) ; pMouth->setColorIndex (1) ; // add the entities to the new block table record if ( (es =pBlockTableRecord->appendAcDbEntity (pFace)) != Acad::eOk ) { //delete pFace ; // all these 'delete ...' not needed any more ... //delete pLeftEye ; //delete pRightEye ; //delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pFace->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pLeftEye)) != Acad::eOk ) { //delete pLeftEye ; //delete pRightEye ; //delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pLeftEye->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pRightEye)) != Acad::eOk ) { //delete pRightEye ; //delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pRightEye->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pMouth)) != Acad::eOk ) { //delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pMouth->close () ; Thanks you all that hepled. B/Rgds Max ----- Original Message ----- From: Max <loadcom(a)sina.com> To: Emil Dotchevski<emildotchevski(a)gmail.com> Subject: Re: [Boost-users] [shared_ptr] Is it possible for a shared_ptr to Date: 2008-12-26 09:22:00 Hello Dotchevski, Thanks for your explanation. This question was pushed to me by seeing the following code in an Autodesk AutoCAD ObjectARX sample program. Don't pay much attention to the descrete classes, just to the new/delete operations. I found the if/delete guards to prevent memory leakage too tedious. I hope there's a smart_ptr-like technique that could help me circumvent this verbose coding style. In other words, my need could be described as: 1) allocate objects dynamically on heap, 2) send them to algorithms that are prone to failure 3) if the opreation succeeds, the objects will be taken care of by the receiver of these objects, or, otherwise, they will be automatically freed without having to delete these objects manually. AcDbCircle *pFace =new AcDbCircle (AcGePoint3d::kOrigin, AcGeVector3d::kZAxis, 1.0) ; AcDbCircle *pLeftEye =new AcDbCircle (AcGePoint3d (0.33, 0.25, 0.0), AcGeVector3d::kZAxis, 0.1) ; AcDbCircle *pRightEye =new AcDbCircle (AcGePoint3d (-0.33, 0.25, 0.0), AcGeVector3d::kZAxis, 0.1) ; AcDbArc *pMouth =new AcDbArc (AcGePoint3d (0, 0.5, 0), 1.0, 3.141592 + (3.141592 * 0.3), 3.141592 + (3.141592 * 0.7)) ; // Set the color property. pFace->setColorIndex (2) ; pLeftEye->setColorIndex (5) ; pRightEye->setColorIndex (5) ; pMouth->setColorIndex (1) ; // add the entities to the new block table record if ( (es =pBlockTableRecord->appendAcDbEntity (pFace)) != Acad::eOk ) { delete pFace ; delete pLeftEye ; delete pRightEye ; delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pFace->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pLeftEye)) != Acad::eOk ) { delete pLeftEye ; delete pRightEye ; delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pLeftEye->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pRightEye)) != Acad::eOk ) { delete pRightEye ; delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pRightEye->close () ; if ( (es =pBlockTableRecord->appendAcDbEntity (pMouth)) != Acad::eOk ) { delete pMouth ; pBlockTableRecord->erase () ; pBlockTableRecord->close () ; return (es) ; } pMouth->close () ; Thanks for your patience! Best regards Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[asio]: Having trouble getting started with ssl
by Roland Bock 29 Dec '08

29 Dec '08

Hi, I tried to follow the documentation for ssl in boost::asio (Overview/SSL), coming up with a few lines of code which fail to compile with boost-1.36 (gcc-4.2.4, Ubuntu8.04, 64bit) with the following message: sslTest.cpp:13: error: invalid initialization of reference of type ‘boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >&’ from expression of type ‘boost::asio::basic_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >’ The message is pretty clear, but I have no idea yet how to fix the problem. Here is the code: // ----------------------------------------- #include <boost/asio.hpp> #include <boost/asio/ssl.hpp> using namespace std; using namespace boost::asio; int main() { io_service ioService; ssl::context ctx(ioService, ssl::context::sslv23); ssl::stream<ip::tcp::socket> sslSock(ioService, ctx); ip::tcp::socket& sock = sslSock.lowest_layer(); } // ----------------------------------------- Regards, Roland

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Seeking example graph program for newbies
by Roger House 29 Dec '08

29 Dec '08

I've just purchased The Boost Graph Library book and downloaded the CD from the publisher's website onto my Ubuntu system. I had to go through a number of contortions to unpack the CD because it is in a "sit" file format and it seems that there is no readily available free software for operating on sit files. I was a bit surprised to discover that the CD does not seem to contain a complete example program which I can compile and run to see that I'm able to access the boost header files and libraries on my system. There is a pdf version of the book, but as far as I can see, there is no example of a complete, simple "hello, graph" program in the book or on the CD. Could someone please point me to such a program. Thank you, Roger House Software Developer

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Re: [Boost-users] [shared_ptr] Is there an interface to set the ptr a
by Max 29 Dec '08

29 Dec '08

Sorry, this version is incorrect: it should be #define DECLARE_VAR_AUTO_CLEANER_BY_MEM_FN(CLASS, VAR, MEM_FN_CLEANER)\ boost::shared_ptr<CLASS> auto__cleaner__for__ ## VAR\ (&VAR, boost::bind(&CLASS::MEM_FN_CLEANER, _1)); #define DECLARE_PTR_AUTO_CLEANER_BY_MEM_FN(CLASS, VAR_PTR, MEM_FN_CLEANER)\ boost::shared_ptr<CLASS> auto__cleaner__for ## VAR_PTR\ (VAR_PTR,\ boost::lambda::if_then(boost::lambda::_1!=static_cast<CLASS*>(0),\ boost::lambda::bind(&CLASS::MEM_FN_CLEANER, boost::lambda::_1))) // use case: struct A { void close() { delete this; } }; { A *pa = new A(); DECLARE_PTR_AUTO_CLEANER_BY_MEM_FN(A, pa, close); } // pa is cleaned by its close() function automatically Max ============================================================= Further, I've written the following macros for such use case: #define DECLARE_VAR_PTR_WITH_AUTO_MEM_CLEANER(CLASS, VAR_PTR, MEM_FN_CLEANER)\ CLASS *VAR_PTR;\ boost::shared_ptr auto__cleaner__for__ ## VAR_PTR\ (VAR_PTR, boost::bind(&CLASS::MEM_FN_CLEANER, _1)); #define DECLARE_VAR_WITH_AUTO_MEM_CLEANER(CLASS, VAR, MEM_FN_CLEANER)\ CLASS VAR;\ boost::shared_ptr auto__cleaner__for__ ## VAR\ (&VAR, boost::bind(&CLASS::MEM_FN_CLEANER, _1)); Usage: DECLARE_VAR_PTR_WITH_AUTO_MEM_CLEANER(AcDbBlockTable, pBlockTable, close); Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[Serialization]Serializing from base class pointers clips derived class
by Daniel Roberts 29 Dec '08

29 Dec '08

The serialization example, test_no_rtti.cpp, appears to only write the base class XML element when saving from the base class pointer. Perhaps I am misunderstanding the point of the extended_type_info classes but I thought it was a way to serialize classes with a common base class without having to know the type of the derived class. The example in test_no_rtti.cpp clips the derived portion of the class when serializing from a base class pointer. Please advise. Thanks.

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Re: [Boost-users] [shared_ptr] Is there an interface to set the ptr a shared_ptr holds
by Max 29 Dec '08

29 Dec '08

Hello Scott， Thanks. It seems to be one of the simplest way to get to my needs to declare another companion auto_free_helper. It's better than none, if not the best. I'm using this technique for stream: std::ofstream outstream(strPath); boost::shared_ptr<std::ofstream> os_auto_closer(&outstream, boost::bind(&std::ofstream::close, _1)); B/Rgds Max ----- Original Message ----- From: Scott McMurray <me22.ca+boost(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [shared_ptr] Is there an interface to set the ptr a shared_ptr holds Date: 2008-12-29 11:35:53 On Sun, Dec 28, 2008 at 22:29, Max <loadcom(a)sina.com> wrote: > > I have the following code scenario: > > A *pa = NULL; > > // pa will be allocated here (by 3rd-party function) > // by setA(), > // whose behavior could not be changed > setA(pa); // prototype: void setA(A*& pa) > > //... > > pa->close(); > I think the following is fine: A *pa_ = 0; setA(pa_); boost::shared_ptr<A> pa(pa_, boost::bind(&A::close, _1)); Since the shared_ptr constructor will call the deleter if its internal allocation fails. ~ Scott _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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Re: [Boost-users] [shared_ptr] Is there an interface to set the ptr a
by Max 29 Dec '08

29 Dec '08

Further, I've written the following macros for such use case: #define DECLARE_VAR_PTR_WITH_AUTO_MEM_CLEANER(CLASS, VAR_PTR, MEM_FN_CLEANER)\ CLASS *VAR_PTR;\ boost::shared_ptr<CLASS> auto__cleaner__for__ ## VAR_PTR\ (VAR_PTR, boost::bind(&CLASS::MEM_FN_CLEANER, _1)); #define DECLARE_VAR_WITH_AUTO_MEM_CLEANER(CLASS, VAR, MEM_FN_CLEANER)\ CLASS VAR;\ boost::shared_ptr<CLASS> auto__cleaner__for__ ## VAR\ (&VAR, boost::bind(&CLASS::MEM_FN_CLEANER, _1)); Usage: DECLARE_VAR_PTR_WITH_AUTO_MEM_CLEANER(AcDbBlockTable, pBlockTable, close); Max Hello Scott， Thanks. It seems to be one of the simplest way to get to my needs to declare another companion auto_free_helper. It's better than none, if not the best. I'm using this technique for stream: std::ofstream outstream(strPath); boost::shared_ptr os_auto_closer(&outstream, boost::bind(&std::ofstream::close, _1)); B/Rgds Max ----- Original Message ----- From: Scott McMurray To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [shared_ptr] Is there an interface to set the ptr a shared_ptr holds Date: 2008-12-29 11:35:53 On Sun, Dec 28, 2008 at 22:29, Max wrote: > > I have the following code scenario: > > A *pa = NULL; > > // pa will be allocated here (by 3rd-party function) > // by setA(), > // whose behavior could not be changed > setA(pa); // prototype: void setA(A*& pa) > > //... > > pa->close(); > I think the following is fine: A *pa_ = 0; setA(pa_); boost::shared_ptr pa(pa_, boost::bind(&A::close, _1)); Since the shared_ptr constructor will call the deleter if its internal allocation fails. ~ Scott _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ ) ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[shared_ptr] Is there an interface to set the ptr a shared_ptr holds
by Max 29 Dec '08

29 Dec '08

Hello, I have the following code scenario: A *pa = NULL; // pa will be allocated here (by 3rd-party function) // by setA(), // whose behavior could not be changed setA(pa); // prototype: void setA(A*& pa) //... pa->close(); I want to apply shared_ptr to make it easier to maintain, or, more specifically here, to save a close() call. new version: boost::shared_ptr<A> pa(NULL, boost::bind(&A::close, _1)); setA(pa.get()); // because get() returns T* instead of T*&, // this line chokes the compiler //pa->close(); not needed any more Is there any way to get my goal accomplished? Thanks for any help. B/Rgds Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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Re: [Boost-users] [shared_ptr] Is it possible for a shared_ptr to
by Max 29 Dec '08

29 Dec '08

Thank you all for your information. Of course, new elegant solution or just simple hints are still welcome. B/Rgds Max ----- Original Message ----- From: Andy Wiese <andyw(a)mitosystems.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [shared_ptr] Is it possible for a shared_ptr to hand over it ownership Date: 2008-12-28 04:54:08 On Dec 27, 2008, at 2:17 PM, Alan M. Carroll wrote: > I don't see why you would ever want to do that. Why not hand over > ownership to another shared_ptr? Why can B in your example not be of > type shared_ptr<>? Then you can hand over ownership by > > b = p1; > p1 = 0; > > Or, if B must be a class, why not have a member that's a shared_ptr > and have getOwnership(shared_ptr& src) do > > _member = src; > src = 0; > > The object can be explicitly destroyed by assigning 0 to _member. > > I would recommend against using auto_ptr, as it is just so _odd_. I > used it once when Boost.scoped_ptr wasn't quite what I wanted, but > that was a mistake (although I did find a nifty bug in the Microsoft > compiler implemementation of auto_ptr). > I find auto_ptr's strict semantics to be useful in APIs because it makes a clear statement about the lifecycle of an object. If some function returns an auto_ptr, then you know right there that the client has full authority over that objects lifecycle. > At 06:57 AM 12/25/2008, Max wrote: >> Suppose I have a shared_ptr which is the only owner of the pointee. >> I hope there is a way to hand over its ownership to another object >> without rendering the pointee being deleted. >> >> Or, if the answer is no, is there an alternative class that has >> this feature? >> >> The use case is like this: >> >> B b; >> { >> shared_ptr p1(A()), p2(A()); >> >> b.GetOwnership(p1.HandOver()); >> // now p1 is empty >> } >> // p2 is deleted here >> >> // but the A obj p1 used to be pointing to >> // has been handed over to b and is still >> // alive here >> >> b.DestroyA(); >> // the A obj holded by b is destroyed by b >> // explicitly > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[Serialization] How non-portable is the non-portable Binary Archive?
by James Madison 28 Dec '08

28 Dec '08

I am interested in using boost serialization for a project I am currently working on, but two requirements are hurting me. First, the archives have to be portable. Second, it's critical to keep the message size under a certain threshold which the text archives blow through. So I am wondering if I can somehow get away with using a binary archive, even though my choices seem to be a non-portable version, or a unsanctioned tested version. Oh, and I am pretty much stuck using Boost 1.32. So, basically, I am wondering: 1. How non-portable is the non-portable archive? While this is a mixed windows/linux environment, all the computers are running as x86 or x86_64, so the endian is the same and word boundary restrictions are mostly the same. Unfortunately, the mapping of data types might not be the same. Is there a simple way to test this if the answer is "maybe"? 2. How stable is the portable archive? Reading through the release notes for 1.37 it seems like that the code is solid, except for encoding doubles, which would not be a problem. Of course, I am being forced to use 1.32, which might be much more unstable . . . Thanks in advance for any replies.

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