February 2002 - Boost-users

Unable to compile thread example on the document.
by 御風只配做笨木頭 04 Feb '02

04 Feb '02

Hi, I cannot compile the thread example listed on the document: http://www.boost.org/libs/thread/doc/thread.html#Example I'm using g++ 2.95.3 on a FreeBSD 4.x box. Here are the exact environment and compile error messages: % uname -a FreeBSD XXX.foo.bar 4.5-PRERELEASE FreeBSD 4.5-PRERELEASE #0: Tue Jan 8 03:14:40 CST 2002 root@XXX.foo.bar:/usr/src/sys/compile/kernel.XXX i386 % g++ -v Using builtin specs. gcc version 2.95.3 20010315 (release) [FreeBSD] % cat test_thread0.cpp #include <boost/thread/xtime.hpp> #include <boost/thread/thread.hpp> #include <iostream> struct thread_alarm { thread_alarm(int secs) : m_secs(secs) { } void operator()() { boost::xtime xt; boost::xtime_get(&xt, ::boost::TIME_UTC); xt.sec += m_secs; boost::thread::sleep(xt); std::cout << "alarm sounded..." << std::endl; } int m_secs; }; void run() { int secs = 5; std::cout << "setting alarm for 5 seconds..." << std::endl; boost::thread thrd(thread_alarm(secs)); std::cout << "main()" << std::endl; thrd.join(); } int main() { run(); } % g++ -I/usr/local/include test_thread0.cpp test_thread0.cpp: In function `void run()': test_thread0.cpp:28: request for member `join' in `thrd', which is of non-aggregate type `boost::thread ()(thread_alarm)' The boost library is installed through FreeBSD's ports collection which the boost version is 1.26.0. I've tried to figure out where the problem is and failed to find the definition of class thread. Do I miss something? Or, is it just a freebsd porting problem? ps. The example seems lack of a xtime inclution. So I add the #include at the first line: #include <boost/thread/xtime.hpp> -- Chien-Chou Hung / Jeff Hung / 洪健洲 (Big5) National Chiao Tung University Institute of Information Management 交通大學資訊管理所碩士生 http://www.jeffhung.idv.tw/ mailto:jeffhung.iim90g@nctu.edu.tw

2 1

Four Questions on boost::shared_ptr
by Jon Wang 04 Feb '02

04 Feb '02

Hi, I've got several questions about the former version of boost::shared_ptr. Would someone please help me? 1. Mr Stroustrup said that there wasn't a need for auto_array, for "a better solution is to use a vector". So, should we use vector or scoped_array/shared_array? 2. In the document, four implementations are said to have been discussed: Direct detached, Indirect detached, Embedded detached and Placement detached. I've tried to describle them (Are I right? See the attached file), but I don't understand the Placement detached. Could someone please tell me what it's like? 3. In the file smart_ptr.hpp, we can see the private function shared_ptr::share. void share(T* rpx, long* rpn) { if (pn != rpn) { ++*rpn; // done before dispose() in case rpn transitively // dependent on *this (bug reported by Ken Johnson) dispose(); px = rpx; pn = rpn; } } // share I'm sorry that I don't understand that reason why ++*rpn should be done before dispose(). Would someone please give me an example? Or is it like this? #include <boost/smart_ptr.hpp> struct A { boost::shared_ptr<A> v; }; int main() { A* pa = new A; boost::shared_ptr<A> ptr(pa); ptr = pa->v; } 4. Why not use policies? I'm afraid that the word "parameterization will discourage users" might not be always true, for we can use default parameters. Jon Wang 2002-01-31

1 0

Fw: Warning to all list owners and moderators
by Ihsan Ali Al Darhi 04 Feb '02

04 Feb '02

I don't know if this is true, but I received it on another group.... > > > > > > I don't know how valid this is but those of you > who belong to yahoo groups > might > want to pass it along to your list owners. > > > > I just got this from another group owner. I have > > heard of this happening, > > > and in one case banned a guy that made a similar > > attempt with one of my > > > groups. > > > Someone has been joining communities with the > nickname YAHOO COMMUNITY > MONITOR, and then posting the following: Yahoo > Community Monitor says: > Yahoo Group Managers have been receiving a few > complaints about your > group.I am required to join your site and monitor > it for about one month.I > will not do anything to damage or ruin your site,I > am only required to > monitor it.The only thing required of you is to > accept my application and > make me a Manager of your group for the time I am > there. If you cannot > meet > these requirements,Yahoo will have to shut your > group down. > DO NOT!! make this person a manager! SHE/HE is a fake, and has been deleting groups once made a manager. BAN the member immediately. Please let other groups know about this problem. I just wanted to let ya'll know. Wouldn't want anything to happen to your groups. Mohammed

1 0

Re: [Boost-Users] Suggestion -- Boost Building
by John Maddock 02 Feb '02

02 Feb '02

>> I used to be able to build this, but since the boost.build stuff came along, > I've been completely unable to build anything at all. The documentation is > worse than useless because it's so self-contradictory.... Don't forget that the regex makefiles are still there if you want them, there is nothing that says that you have to use Jam if you don't want to... - John Maddock http://ourworld.compuserve.com/homepages/john_maddock/

1 0

boost python and smart pointers
by Martin Strubel 01 Feb '02

01 Feb '02

Hello, I've lately experimented with Boost.Python and found it pretty useful. Though I've run into one thing which I couldn't figure out by the documentation, I hope someone can give me a hint there: I have a function returning a pointer to an 'owned' structure, i.e. its container takes care of creation and deletion. In Python, I want to wrap this pointer into a direct reference to the struct, i.e. no copying. To guard the access and make sure the object can't be accessed after the deletion, I want to wrap the smart pointer AS a python object. for example, a C++ function returning an 'owned' face from a mesh: FaceSmartPtr Mesh::addFace() { .. } should be wrapped for access in Python like: f = mesh.addFace() with subsequent calls for face manipulation like: f.addVertex((0.0, 0.0, 0.0)) where this should again call something like if (f_sptr.isValid()) f_sptr->addVertex(...); else throw_pyException_ptrInvalid(); Does Boost support this automatically ? Or do I have to wrap all these functions myself ? Greetings, - Strubi -- Martin Strubel, Software Hooligan strubi(a)blender.nl www.blender.nl Not a Number - 3D Enabling Technology tel. +31 40 2501231 Eindhoven, The Netherlands

1 0

RE: [Boost-Users] Suggestion -- Boost Building
by Wismar, John 01 Feb '02

01 Feb '02

In my case (the most recent how-can-I-build-this question) I'm trying (unsuccessfully) to use the regex library, which requires compiling.... I used to be able to build this, but since the boost.build stuff came along, I've been completely unable to build anything at all. The documentation is worse than useless because it's so self-contradictory.... -------------------------- John Wismar mailto:jwismar@alldata.com > -----Original Message----- > From: Duane Murphy [mailto:duanemurphy@mac.com] > Sent: Saturday, January 26, 2002 12:15 AM > To: Boost Users > Subject: [Boost-Users] Suggestion -- Boost Building > > > It seems a lot of questions come up on the list about > "building" the boost libraries. > > I wonder how many of these people realize that most of the > functionality of the Boost "libraries" is completely > encapsulated in the header files? There are significant > portions like regex and the graph library (?) that do require > compiling, but much of it does not. > > Is there anything that can be done to make it more clear that > compiling is often not necessary? > > I'm just trying to relieve some stress from people who may > very well not require compiling. And I have compassion for > those that do and are having trouble. > > I'm not sure exactly what can be done, but it might be worth > some thought. > > ...Duane > > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> Sponsored by VeriSign - The Value > of Trust Pinpoint the right security solution for your > company - FREE Guide from industry leader VeriSign gives you > all the facts. > http://us.click.yahoo.com/lWSNbC/WdiDAA/yigFAA> /EbFolB/TM > > > -------------------------------------------------------------- > -------~-> > > Info: <http://www.boost.org> > Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> > Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> > > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > >

2 1