June 2002 - Boost-users - lists.preview.boost.org

boost::threads - a few more questions....
by Peter 18 Jun '02

18 Jun '02

I have a few more questions regarding boost::threads: 1) Is is at all possible to get a return value from a function which was passed into a thread - for example after calling thread.join() ?? 2) Assuming that I create a thread from within another thread ( for exaple: from within the "main" thread - main()); is there a mechanism for that newly created thread to notify my "main" thread that it has finished execution?? Is there some sort of library (I am looking for something platform independent) which would allow me to do that?? 3) I would lie to run two threads in a client application. One would be responsible for receiving and the other for sending data. The threads would basically run in infinite loops. Both sending and receiving would be done to/from the SAME socket. My question is: Do i still have to lock the mutex during each opperation?? I have been doing a LOT of testing WITHOUT locking it and have not had my program crash (yet). Is that because the kernel (running win2000 and using the winsock API) is somehow dealing with all the overhead of locking/unlocking the socket, or have I just been lucky?? Thanks in advance for any suggestions. Best to you all Peter

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RE: [Boost-Users] boost::threads queation
by Mark Storer 18 Jun '02

18 Jun '02

This has little to do with boost (which, again, is why I can answer; at least in part) A member function cannot be addressed like a regular function. Ask yourself this question: With just a function pointer to go by, what will the compiler use for 'this'? The Good News: STL contains a template functor to take care of this for you: "std::mem_fun". I haven't messed with it personally, but the docs sure make it sound like it would do the trick. The Bad News: I'm not so sure the thread class will let you use it. I'm not familiar with the function0<> template, so I don't know whether or not std::mem_fun will work with boost::thread. Anybody care to chime in here? --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard; -----Original Message----- From: Peter [mailto:yg-boost-users@m.gmane.org] Sent: Monday, June 17, 2002 9:09 PM To: boost-users(a)yahoogroups.com Subject: [Boost-Users] boost::threads queation Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter 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/

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Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function
by Peter Dimov 18 Jun '02

18 Jun '02

Your problem was that the EXE was using the single-threaded runtime, but the DLL has been set to multithreaded. The mutex lock in the DLL was spinning forever. When I set both to multi-threaded, it works, even with different heaps. Interesting issue. It can be made to work even in this case but this will cost performance. ----- Original Message ----- From: <corno(a)dds.nl> To: "Peter Dimov" <pdimov(a)mmltd.net> Sent: Tuesday, June 18, 2002 13:52 Subject: Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function > hmmmm.... > 2nd try :) > > > Did you forget the attachment? ;-) > > > > ----- Original Message ----- > > From: <corno(a)dds.nl> > > To: <pdimov(a)mmltd.net> > > Sent: Tuesday, June 18, 2002 0:39 > > Subject: Re: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll > > function > > > > > > > > > > > > Thanx Craig, that turned out to be the problem for VC++ as well. > > > > > > > > Yep, but shared_ptr is supposed to work in this case, in theory. ;-) > > I'll > > > > look into this. Any more information that can help me find the problem? > > > > > > > > > > Peter, > > > > > > I made 2 small projects that illustrate the problem. (change the path to > > the > > > boost lib ofcourse) > > > It can very likely be that I am doing something terribly stupid :) but > > anyways, > > > here's what I see; > > > > > > If I build and run it with a single memory manager I see output for all 4 > > steps. > > > If I build and run it with separated memory managers I see output for > > step > > 1 > > > and 2 only and then it hangs. > > > > > > Corno > > > > > > > > > > >

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boost::threads queation
by Peter 18 Jun '02

18 Jun '02

Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter

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new to boost::threads - question
by Peter 18 Jun '02

18 Jun '02

Is it possible to pass a pointer of a class member function into a thread ?? I have no problems passing functions (or pointers to functions rather) which are not members of any classes. However when I try to pass member functions, I get compile errors. I am using MSVS 6.0 on win 2000. The following is a simplified model of my situation. I am trying to create a thread inside a function of one class and pass into it, a pointer of a member function of another class: // all necessary includes; class testClass1 { public: // constructor testClass1() { // init code} ~testClass1() {} void fun1() { // some code} }; class testClass2 { testClass2() { // init code} ~testClass2() {} // SEE HERE PLEASE void fun2() { // some code.. boost::thread myThread(&object1.fun1) ; // PROBLEM HERE // more code... } testClass1 object1; }; int main(int argc, char **argv) { testClass2 class2; // some code... class2.fun2(); // more code.... return 0; } Any help would be greatly appreciated. Thanks in advance. Peter

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RE: [Boost-Users] tolower not in std::
by bjorn.karlsson＠readsoft.com 17 Jun '02

17 Jun '02

> From: ccullum [mailto:yg-boost-users@m.gmane.org] > I am getting a message stating that tolower is not found in > the std::, but > transform can be found. Has anyone seen this before? > In future posts, please state the Boost library that is causing trouble. There is already one reply to this seemingly-close-to-being-off-topic note; another possibility is that you've simply failed to #include the header where tolower resides, which is <cctype>. Bjorn [Non-text portions of this message have been removed]

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tolower not in std::
by ccullum 17 Jun '02

17 Jun '02

I am getting a message stating that tolower is not found in the std::, but transform can be found. Has anyone seen this before? Thanks, Christopher cullum ccullum(a)uprizer.com

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[BGL] using Borland C++Builder 5
by Alex Henderson 17 Jun '02

17 Jun '02

Hi, I had a problem compiling both the test file (libs/graph/test/graph.cpp) and the first example (libs/graph/example/file_dependencies.cpp) of the BGL and traced the problem to the support for tuples. The offending line is line 40 of boost/tuple/tuple.hpp which incorporates tuples::get into the boost namespace. Commenting out this line allows the files above to compile and run OK. Leaving it in invokes an internal compiler error. The test file for tuples works OK with Builder 5 and so I guess there's a dependency somewhere. The question is - if I comment out this line am I going to get hit with problems elsewhere in the BGL? I'm new to the BGL and don't know whether the whole thing is built on the abilities of tuples. [Using boost_1_28_0, BCC5 sp1, Win2000 sp2] Thanks for any thoughts. Alex

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RE: [Boost-Users] MS VS 6: passing boost::shared_ptr<T> to a dll function
by Smith, Eric V. 16 Jun '02

16 Jun '02

How about some sample code? It's hard to help if we don't know exactly what you're trying to do. > -----Original Message----- > From: lognez [mailto:corno@dds.nl] > I am trying to pass a smart pointer (boost::shared_ptr<T>) as an > argument to > a function that is implemented by a dll and called by an executable, > but > whenever I execute the application, it goes into a loop, no matter > what the > type of T is. When the function is implemented in the exe or > when the function is called from inside the dll it works > fine. Does anybody have a clue what could be happening? BTW, > I'm not implicating a bug in boost, I know that it could as well > be a > MS VC++ bug but I would just like to know how this comes and how I > can solve > it.

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Re: Static power() function, to add in common_factor
by Daryle Walker 14 Jun '02

14 Jun '02

on 6/12/02 12:11 AM, ravioli(a)softhome.net wrote: > Is there an interest into having a power() template calculating the N-th power > of any number, when N is known at compile-time ?t uses the algorithm of the > STL power function(), and runs between two or three times faster, and maybe > could be of interest in the " <boost/math/common_factor.hpp> which provides > run-time and compile-time evaluation of the greatest common divisor (GCD) or > least common multiple (LCM) Proposals for new libraries usually go to the regular Boost list, not this one. Besides that: What would this have to do with the common-factor library? I've never heard of a function called "power". Is it a STL function that didn't get into the standard? Are there any docs for it? How do you know what algorithm it uses? > It simply works this way, for example to have PI at exponent three : > double a = power_const<3>( 3.14159) > > As the single include file is very short, please apologize if I give it > straight on, just to save your time and to have an idea how badly you judge my > poor code ;) [TRUNCATE code] I don't think your implementation will work for negative exponents. -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT mac DOT com

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