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

thread::join() usage
by rgalek2002 10 Jun '02

10 Jun '02

Hi, I have an application which starts a number of threads, and I want the application to wait for the threads to finish before exiting. Standard stuff, I know, but never having used threads before I am wondering what the stadard way is to accomplish this. I have (psuedo code) for (each record in database) { thread thrd(func(), data); } I could imagine storing all my thread objects in a list, and then calling join() on each one. For example something like list <thread> threads; for (each rec in db) { thread thrd(func(), data); threads.insert(threads.begin(),thrd); } list<thread>::iterator i; for (i=threads.begin(); i!=threads.end(); i++) { thread t = *i; t.join(); } Does this seem reasonable? Is there a better/standard way? One thing I don't like here is that each join will block, when what I would like to do is something more like join_all(); Thanks, Rich

2 1

Intel-win32 Build Problem
by thorneg 09 Jun '02

09 Jun '02

I'm getting errors in xtime.cpp relating to uint64_t when building with the Intel-win32 v6.0 compiler. The errors are: xtime.cpp libs\thread\build\../src\xtime.cpp(80): error: namespace "boost" has no member "uint64_t" const boost::uint64_t TIMESPEC_TO_FILETIME_OFFSET = ((boost::uint64_t)27111902UL << 32) + (boost::uint64_t)3577643008UL; Has anyone else run into this? Any help is appreciated. Glenn

1 0

Dynamic Bitset Formal Review June 8-17
by Mat Marcus 08 Jun '02

08 Jun '02

The formal review of Dynamic Bitset by Chuck Alison and Jeremy Siek will commence today Saturday June 8th and run through Monday, June 17th. The library is currently available at <http://groups.yahoo.com/group/boost/files/dyn_bitset.tar.gz> Below is an excerpt from the library's documentation: The dyn_bitset class represents a set of bits. It provides accesses to the value of individual bits via an operator[] and provides all of the bitwise operators that one can apply to builtin integers, such as operator&& and operator<<. The number of bits in the set is specified at runtime via a parameter to the constructor of the dyn_bitset. Each bit represents either the Boolean value true (set) or false (reset). To toggle a bit is to change the value to true if it is false and to false if it is true. Each bit has a non-negative position pos. The position pos == 0 corresponds to the least significant bit and pos == size() - 1 is the most significant bit. When converting an instance of dyn_bitset to or from an unsigned long, the bit position pos corresponds to the bit value 1 << pos. The dyn_bitset class is nearly identical to the std::bitset class. The difference is that the size of the dyn_bitset (the number of bits) is specified at run-time during the construction of a dyn_bitset object, whereas the size of a std::bitset is specified at compile-time through an integer template parameter. For information about submitting a Formal Review, see http://www.boost.org/more/formal_review_process.htm Please try out the library and comment during the review period. Be sure to say whether or not you think the library should be accepted by Boost. Compiler notes: This library has been tested using the following compiler platforms: Gcc 2.95 and 3.01 Kai C++ Metrowerks Codewarrior 8 (beta, Mac) Visual C++ 7.0 Comeau The library presently requires template friend support and is known not to compile with CodeWarrior 7.2 or Visual C++ 6.0. The library has not been tested with Borland. The Formal Review manager is Mat Marcus.

1 0

MacOS.hpp and PowerPlant incompatibility
by Bobby Thomale 08 Jun '02

08 Jun '02

I am trying to use the boost libraries with a PowerPlant project on the MacOS, and I ran into a small incompatibility between the headers. I am not sure which codebase is at fault here. The issue is with the __MACH__ symbol. In the Boost code where it is checking for what platform I am using, it correctly identifies my platform as MacOS. Then, in a file called MacOS.hpp, it uses the __MACH__ symbol to determine if I am using the BSD standard C libraries or MSL. (I am using MSL.) It does this by checking for the EXISTANCE of the __MACH__ symbol, not the value of it: // If __MACH__, we're using the BSD standard C library, not the MSL: #if defined(__MACH__) However, in the PowerPlant header PP_Macros.h, the __MACH__ symbol is defined and set to zero: #ifndef __dest_os // For MSL #ifndef __MACH__ #define __MACH__ 0 #endif #if __MACH__ #include <ansi_prefix.mach.h> #else #define __dest_os __mac_os #endif #endif I was able to work around the problem for now by making the Boost libraries check for both the existance of __MACH__ and the value: #if defined(__MACH__) && __MACH__ Seems to work. However, I am curious. Which way is the right way? Is the __MACH__ symbol's existance or its value supposed to signal whether or not it is "turned on"? The boost headers seem to think it is its existance, but the PowerPlant headers seem to think it is its value. I want to report the problem, but I am not sure whose code needs to change, PowerPlant or Boost. Ideas? -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ ---------------------------------------------------------------------

4 5

[BGL] How can I use vertex object rather than integer?
by �ڱ�� 07 Jun '02

07 Jun '02

for example, class Node { public: int m_id; }; class Edge { public: int from_node_id; int to_node_id; }; How can I use this class to make graph? many examples show only integer id graph.. thanks in advance ---------------------------------------- Ki-Soo, Park HP: 82-11-9040-4957 e-mail: park(a)erhouse.co.kr wfms123(a)hotmail.com

4 3

[BGL] how to use visitor with functor?
by �ڱ�� 06 Jun '02

06 Jun '02

Can I use visitor with functor ? In BGL example on visitor, int main() { : boost::breadth_first_search (G, vertex(0, G), visitor(make_bfs_visitor( std::make_pair(print_edge("tree", on_tree_edge()), print_edge("cycle", on_non_tree_edge()))))); : } I want to do like this boost::breadth_first_search (G, vertex(0, G), visitor(make_bfs_visitor( std::make_pair(print_edge("tree", on_tree_edge(), MyFunctor1() ), print_edge("cycle", on_non_tree_edge(), MyFunction2() ))))); can i do this? how? why? thanks in advance.. ps. ths is my first posting. ---------------------------------------- Ki-Soo, Park e-mail: park(a)erhouse.co.kr wfms123(a)hotmail.com

2 1

Boost::Python constructor overloading problems
by John Hunter 06 Jun '02

06 Jun '02

I have been using boost python for some time now and recently upgraded to boost_1_28_0 and gcc 3.0.4. I started getting a segmentation fault when using a library with an overloaded constructor. In trying to track down the source of the problem, I wrote a simple class with an overloaded constructor and still get the seg fault. Perhaps there is something wrong with code or the compile statement, but I have been unable to find. it. So I've also included some additional info below that may give someone a clue as to what is going wrong. Here is the python script which calls the simple class. The second constructor crashes with a seg fault: from TestSimple import Simple # Default constructor OK d1 = Simple() print d1.get() i = 1 d2 = Simple(i) # this line causes the seg fault print d2.get() ---- Here is the code I use to make the module TestSimple: #include <boost/python/class_builder.hpp> class SimpleClass { public: SimpleClass() : i(-1) {}; SimpleClass(int i) : i(i) {}; int get() const { return i; } private: const int i; }; namespace python = boost::python; BOOST_PYTHON_MODULE_INIT(TestSimple) { python::module_builder m( "TestSimple" ); python::class_builder<SimpleClass> simple(m, "Simple"); simple.def(python::constructor<>()); simple.def(python::constructor<int>()); simple.def(&SimpleClass::get, "get"); } ---- Here are the compile commands: /usr/local/bin/g++ -I/usr/local/include/python2.1 -I/usr/local/include -ggdb -Wall -fPIC -ftemplate-depth-21 -c TestSimplePy.cpp /usr/local/bin/g++ -shared -L/usr/local/lib -ggdb -Wall -fPIC -ftemplate-depth-21 TestSimplePy.o -o TestSimple.so -lboost_python ---- I run the script in a controlled environment with: #!/bin/sh export LD_LIBRARY_PATH=/usr/local/lib /usr/local/bin/python2.1 ./testSimple.py ---- Here is the ldd for the TestSimple module: mother:~/c/trade/test> ldd TestSimple.so libboost_python.so.1.28.0 => /usr/local/lib/libboost_python.so.1.28.0 (0x40011000) libstdc++.so.3 => /usr/local/lib/libstdc++.so.3 (0x40078000) libm.so.6 => /lib/i686/libm.so.6 (0x40112000) libgcc_s.so.1 => /usr/local/lib/libgcc_s.so.1 (0x40136000) libc.so.6 => /lib/i686/libc.so.6 (0x4013e000) libutil.so.1 => /lib/libutil.so.1 (0x4026e000) /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x80000000) ---- All the version info looks right -- python2.1 was compiled with the same gcc (3.0.4) that the module was. Thanks for any suggestions, John Hunter

2 4

CW project file
by NOEL Bruno 06 Jun '02

06 Jun '02

Hello, As I am much more familiar with the Metrowerks IDE than with standard makefiles, has anyone made a .mcp project file able to compile whole of the boost library with Codewarrior ? Thanks for the answers and possible files ! Bruno NOËL

1 0

Re: problem with c_regex_traits.cpp
by René Gutschmidt 06 Jun '02

06 Jun '02

>> i have problems with the file c_regex_traits.cpp. I work under CodeWarrior >> 6/7 with a Macintosh. >> These problem ist with boost 1.25.1,1.26. >> >> template <class charT> >> unsigned int BOOST_REGEX_CALL re_get_message(charT* buf, unsigned int >> len, unsigned int id) >> { >> unsigned int size = _re_get_message((char*)0, 0, id); >> if(len < size) >> return size; >> boost::scoped_array<char> cb(new char[size]); >> _re_get_message(cb.get(), size, id); >> size = boost::c_regex_traits<wchar_t>::strwiden(buf, len, cb.get()); >> return size; >> } >> >> inline unsigned int BOOST_REGEX_CALL re_get_message(char* buf, unsigned >> int len, unsigned int id) >> { >> return _re_get_message(buf, len, id); >> } >> >> Is that a known problem? Do you know a workaround? >> (Renaming one of the 're_get_message()' functions does >> the job, but I'm not sure about the implications.) > > I've had a chance to experiment a little with this - if BOOST_NO_WREGEX is > defined (i.e. wide character support is disabled), then removing the > template version of re_get_message is harmless (and may therefore be the fix > that you are looking for). If BOOST_NO_WREGEX is not defined, then > obviously this won't work - so that being the case, what happens if you > surround the definition of > > template <class charT> > unsigned int BOOST_REGEX_CALL re_get_message(charT* buf, unsigned int len, > unsigned int id) > > with > > #ifndef BOOST_NO_WREGEX > ... > #endif > > regards, > > John Maddock Sorry, but I haven't had a chance to answer. Ok it's works. But I need 'wide character support' much later. best regards, Rene Gutschmidt

2 4

RE: [Boost-Users] Re: boost::noncopyable usage question
by Michael Davis 06 Jun '02

06 Jun '02

Thank you for the clarification. :) -----Original Message----- From: Darin Adler To: Boost-Users(a)yahoogroups.com Sent: 6/6/2002 12:57 AM Subject: Re: [Boost-Users] Re: boost::noncopyable usage question On Wednesday, June 5, 2002, at 03:14 PM, Michael Davis wrote: > According to the C++ Standard, 12.8/10, the assignment operator cannot > be > inherited because if it is not provided, the compiler will provide one > implicitly. Or at least, that is my understanding of it. > > Given this, how can boost::noncopyable work? The assignment operator provided by the compiler for the class derived from noncopyable has to copy the part of the object that's inherited from noncopyable. To do that, it has to use the assignment operator from the noncopyable class; but if it's inaccessible, like the private one in noncopyable, it has to report an error. This rule is mentioned in 12.8/14. -- Darin 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/

1 0

type_traits::is_POD<> problem
by s9801758 06 Jun '02

06 Jun '02

Hello, I'm using MSVC6.0 with service-pack 6.0 installed. But I'm getting some weird problems. Consider the following simple program: ---------------------------------------------------- struct q { int x; }; int main() { int t; t = boost::is_POD< int >::value; // Ok, t = true; t = boost::is_POD< void >::value; // Ok?, t = true (is 'void' considered a POD?); t = boost::is_POD< q >::value; // Error, t = false } ---------------------------------------------------- Unless my definition of a POD type is incorrect, I think that q is considered POD, right? Am I doing something wrong here, or is the combination boost and msvc fatal once again? Just to be complete, I have the following defines in my main header: #define BOOST_NO_FUNCTION_PTR_TEMPLATE_PARAMETERS #define BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION Thanks in advance, Jaap Suter

2 1

Boost regex and MacOS X.
by Mystical Catty Tananeka 06 Jun '02

06 Jun '02

I've been trying to make MacOS X compile the example snippets from boost_1_28_0/libs/regex/example/snippets/ and I keep getting these messy link errors. It looks like /usr/bin/c++ is having trouble linking to libboost_regex.a here's an example: localhost% c++ -o regex_grep_example_1 regex_grep_example_1.cpp -lboost_regex /usr/bin/ld: Undefined symbols: __._Q25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9allocator1Zc ___Q25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9allocator1ZcPCc UiRCB2 ___Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcRCB1 _allocator__CQ25boostt14reg_expression3ZcZQ25boostt12regex_traits1ZcZt9alloc ator1Zc _allocator__CQ35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _cow__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _m_free__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1Zc _set_first__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcPCc _set_first__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcPCcUl _set_size__Q35boost9re_detailt18match_results_base2ZPCcZt9allocator1ZcUlPCcn 1 localhost% I haven't enough experience with boost to know how to fix this, or even what it means, exactly. If its informative, c++ -v returns: Apple Computer, Inc. version gcc-934.3, based on gcc version 2.95.2 19991024 (release)

2 1

BGL: subgraph<..> Problems
by Matthias Kronenberger 06 Jun '02

06 Jun '02

1. How to create a subgraph from a given simple boost graph type? 2. Why are modell subgraph not the same concept as the underlying graph type? Why are not all non-member function defined for the only graph modell adjacence_list<> also available for subgraph? 3. I've defined something like class NG { public: typedef boost::property<boost::vertex_all_t, SomeIterator, Vertex_Property > vertex_SPIterator_Prop; // GridSP_type::iterator typedef Default::Graph<vertex_SPIterator_Prop, Edge_Property>::Subgraph::Undirected Graph; ... }; where struct Default { ..... template<class VertexProperties=boost::no_property, class EdgeProperties=boost::no_property, class GraphProperties=boost::no_property, class EdgeList=boost::hash_setS, class VertexList=boost::listS > struct Graph { ........ struct Subgraph { typedef typename boost::subgraph < boost::adjacency_list<EdgeList, VertexList, boost::undirectedS, boost::property<boost::vertex_index_t,int, VertexProperties>, boost::property<boost::edge_index_t, int, EdgeProperties > ,GraphProperties> > Undirected; }; .... }; and then i'm doing somewhere else { vertex_descriptor v=boost::add_vertex( theGraph); IteratorMap[Prop ] =v; boost::put( boost::vertex_all_t() , theGraph, v, Prop); return v; } I get a nice error with MSVC 6.5 d:\matthias\programmieren\boost\boost\graph\subgraph.hpp(751): error C2679: Binaerer Operator '=': Kein Operator definiert, der einen rechtsseitigen Operator vom Typ 'const _Ht_iter<pair<int const,surrect::PNSurfel<vectorD<float,3>>>,_Nonconst_trait............ (no operator= defined for the type conversion used in put pmap[k] = val;) But using a simple adjacence_list<..> instead of the subgraph< adjacence_list<...> this mess compiles fine. What am i doing wrong? Are there better ways to create a property map containing (const) iterators, that don't modell STL::RandomAccesIterator? Matthias

1 0

RE: [Boost-Users] Re: boost::noncopyable usage question
by Michael Davis 06 Jun '02

06 Jun '02

According to the C++ Standard, 12.8/10, the assignment operator cannot be inherited because if it is not provided, the compiler will provide one implicitly. Or at least, that is my understanding of it. Given this, how can boost::noncopyable work?

2 1

RE: [Boost-Users] boost::noncopyable usage question
by Mark Storer 05 Jun '02

05 Jun '02

This is more of a C++ question than a boost one (which is why I can answer it;). Your deletes are fine. The only way this would cause a problem is to delete through a boost::noncopyable pointer (in which case everything derived from it would leak). I'm guessing the author, Dave Abrahams, didn't think anyone was going to declare a noncopyable*, so decided to pass on that little bit of extra overhead involved in declaring a destructor virtual. Or it could be a mistake. Dave has posted to this list at least once... So tell us, did you mean to leave it non-virtual? --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard; -----Original Message----- From: Bobby Thomale [mailto:bthomale@mac.com] Sent: Wednesday, June 05, 2002 9:30 AM To: Boost Users List Subject: [Boost-Users] boost::noncopyable usage question I have a simple question about the usage of boost::noncopyable. I think I know the answer, but I am not sure. The noncopyable class defines a non-virtual destructor. Generally speaking, overriding a non-virtual destructor is considered a "bad thing" but in certain cases (like, I am guessing, this one) it is okay and works like you'd expect. Here's what I am worried about: Let's say I have a base class of an inheritance tree that I want to be non-copyable. So I do this: class MyBase : private boost::noncopyable { public: MyBase (); virtual ~MyBase (); ... }; Then I derive from it class A: class A : public MyBase { public: A (); virtual ~A(); }; and define a destructor for class A, too. Does this do what I would expect, ie whether I delete a MyBase* or an A*, it calls the destructors for both A and MyBase like it is supposed to? I suppose the trivial, empty noncopyable destructor never gets called (which is okay) whether I delete a MyBase* or an A*, correct? (Just curious...) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ --------------------------------------------------------------------- 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/

4 3

boost::noncopyable usage question
by Bobby Thomale 05 Jun '02

05 Jun '02

I have a simple question about the usage of boost::noncopyable. I think I know the answer, but I am not sure. The noncopyable class defines a non-virtual destructor. Generally speaking, overriding a non-virtual destructor is considered a "bad thing" but in certain cases (like, I am guessing, this one) it is okay and works like you'd expect. Here's what I am worried about: Let's say I have a base class of an inheritance tree that I want to be non-copyable. So I do this: class MyBase : private boost::noncopyable { public: MyBase (); virtual ~MyBase (); ... }; Then I derive from it class A: class A : public MyBase { public: A (); virtual ~A(); }; and define a destructor for class A, too. Does this do what I would expect, ie whether I delete a MyBase* or an A*, it calls the destructors for both A and MyBase like it is supposed to? I suppose the trivial, empty noncopyable destructor never gets called (which is okay) whether I delete a MyBase* or an A*, correct? (Just curious...) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ ---------------------------------------------------------------------

2 2

Tupls browsing...
by Igor Korzinek 04 Jun '02

04 Jun '02

Hi, I did not take a look at the tuple internals, but it seems that there is some head-tail connection probably built in compile time. So can someone from template gurus answer if it makes sense and if it is possible to add some method that will make sequential access possible. Some function that will getNext() or some kind of search within a tuple ? Is it too stupid or just impossible ? Igor

1 0

Is it worth using if I use MSVC
by Igor Korzinek 04 Jun '02

04 Jun '02

Hi, I'm new to boost. The doc I've browsed seems fine and something what I need. I'm focusing on TUPLEs part. So, besides mentioned cref and ref stuff, is there any other issue I can expect with awful (but a must for me) MS VC 6 ? And are there any sample for using this part of boost ? THX, Igor

1 1

Newbie Thread Installation Problem
by gclee46 03 Jun '02

03 Jun '02

(Please excuse me it this is a duplicate post - I tried to send it yesterday and it didn't seem to arrive) I have Boost 1_28_0 and installed the prebuilt version of Jam for Windows. After installing threads with C:\boost_1_28_0>bjam "-sTOOLS=borland" I get, after skipping the pyton stuff, and all the install messages: ...found 390 targets... However when I try to use the thread I get the following: Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland testthread1.cpp: Fatal F1003 \boost_1_28_0\boost/thread/thread.hpp 17: Error directive: Thread support is unavailable! *** 1 errors in Compile *** I believe that I followed all the directions...I'm using Windows XP Home. Any help would be greatly appreciated. Greg

1 0

BGL and MS compilers (VC++ and Wince)
by a_schweitzer 03 Jun '02

03 Jun '02

I am having difficulting getting BGL to compiler with VC++ 6.0 and Windows CE 3.0, platform builder. In both cases I get internal compiler errors, although at different lines in the compiler. VC++ worked when I had all my code in one cpp file. When I broke it out into multiple files I couldn't get it to compile even when I put it back in one file. I have tried the Zm and Z7 switches to no avail. Perhaps I need the service pack? Wince dies much more quickly, I think when it sees adjacency_list.hpp or depth_first_search.hpp. Does anyone have some perspective on how BGL projects with MS work out? Is there any hope for Wince?

1 0

Dynamic Bitset - Upcoming Formal Review
by Mat Marcus 03 Jun '02

03 Jun '02

The formal review of Dynamic Bitset by Chuck Alison and Jeremy Siek will commence on Saturday June 8th and run through Monday, June 17th. The library is currently available at <http://groups.yahoo.com/group/boost/files/dyn_bitset.tar.gz> Below is an excerpt from the library's documentation: The dyn_bitset class represents a set of bits. It provides accesses to the value of individual bits via an operator[] and provides all of the bitwise operators that one can apply to builtin integers, such as operator&& and operator<<. The number of bits in the set is specified at runtime via a parameter to the constructor of the dyn_bitset. Each bit represents either the Boolean value true (set) or false (reset). To toggle a bit is to change the value to true if it is false and to false if it is true. Each bit has a non-negative position pos. The position pos == 0 corresponds to the least significant bit and pos == size() - 1 is the most significant bit. When converting an instance of dyn_bitset to or from an unsigned long, the bit position pos corresponds to the bit value 1 << pos. The dyn_bitset class is nearly identical to the std::bitset class. The difference is that the size of the dyn_bitset (the number of bits) is specified at run-time during the construction of a dyn_bitset object, whereas the size of a std::bitset is specified at compile-time through an integer template parameter. For information about submitting a Formal Review, see http://www.boost.org/more/formal_review_process.htm Please try out the library so that you will be prepared to to say whether or not you think the library should be accepted by Boost during the upcoming review period next week Compiler notes: This library has been tested using the following compiler platforms: Gcc 2.95 and 3.01 Kai C++ Metrowerks Codewarrior 8 (beta, Mac) The library presently requires template friend support and therfore is known not to compile with CodeWarrior 7.2. The library has not been tested with VC++ or Borland. The Formal Review manager will be Mat Marcus.

1 0

Compilation question
by rgalek2002 03 Jun '02

03 Jun '02

Hi, I am a new user of the boost libs, so sorry for the supid questions. I am running into a compilation error while trying to compile listing 2 and listing 3 from Bill Kempf's article at http://www.cuj.com/articles/2002/0205/0205a/0205a.htm, giving simple usage examples of boost threads. 1. When I compile listing 2, the compiler chokes on the lines boost::thread thrd1(count(1)); boost::thread thrd2(count(2)); with the errors listing2.C:27: no matching function for call to `count (int)' listing2.C:28: no matching function for call to `count (int)' As you can see in the listing online, count is defined as 'struct count{...}' Upon perusal of threah.hpp, I see that, indeed, the class thread constructor is looking for a function, not a struct or class as count is defined in this code. Am I missing something, or is the code in error? 2. In listing 2, I get the following errors when compiling: listing3.C:29: no matching function for call to `bind ({unknown type}, int)' listing3.C:31: no matching function for call to `bind ({unknown type}, int)' This is in response to the lines: boost::thread thrd1(boost::bind(&count, 1)); boost::thread thrd2(boost::bind(&count, 2)); Again, am I missing something or what? I have pasted the code directly from the source as provided online. TIA for your help Richard

3 2