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Using Bind with Signals (version 2)
by Darren Vincent Hart 30 May '03

30 May '03

Similar to my last post, this is a slightly different implementation where the handler has a signal of its own. Now I can't seem to bind to the handler functor, getting a compiler message like: /usr/include/boost/bind.hpp:60: error: `bool (handler::*)(char)' is not a class, struct, or union type The goal is that when the keypress signal is emitted, it will execute the handler which will receive the char (key), test it, and emit its signal (sig) if appropriate. Any help would again be much appreciated, the short code follow, with the problematic bind statement commented: Thanks in advance, Darren Hart compile: g++ test.cpp -o test -lboost_signals // test.cpp ---------------------------------------------------- #include <iostream> #include <boost/signal.hpp> #include <boost/function.hpp> #include <boost/bind.hpp> #include <boost/bind/apply.hpp> using namespace std; struct widget { boost::signal<bool ()> sig; boost::signal<bool (char)> keypress; bool test() { cout << "widget::test() - sig empty: " << (sig.empty() ? "true" : "false") << endl; sig(); return true; } }; struct handler { char key_; boost::signal<bool ()> sig; handler(char key) : key_(key) { } bool operator()(char key) { cout << "handler::operator() - received a " << key << endl; if (!sig.empty() && key == key_) { cout << "\texecuting slot\n\t"; sig(); } cout << endl; return true; } }; struct no_op { bool operator()() { cout << "no_op::operator() - doing nothing" << endl; return true; } bool test() { cout << "no_op::test()" << endl; return true; } }; int main() { // instantiate two widgets widget widget_a; widget widget_b; // instanstiate the functions object (and test them) no_op no_op_; handler handler_a('A'); handler_a.sig.connect(no_op_); no_op_(); handler_a('A'); // connect the function objects to the widgets widget_a.sig.connect(no_op_); // THE PROBLEM IS HERE - HOW DO I BIND TO handler_a.test(char) ? widget_b.keypress.connect( boost::bind(&handler::operator(), &handler_a) ); // END PROBLEM cout << "signalling widget_b.keypress('B')" << endl; widget_b.keypress('B'); // call the handler 3 times, but never execute its slot cout << "\nsignalling widget_b.keypress('A')" << endl; widget_b.keypress('A'); // call the handler 3 times, executing the slot return 0; }

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Re: Using Bind on Signals
by Peter Dimov 30 May '03

30 May '03

darrenvhart wrote: > --- In Boost-Users(a)yahoogroups.com, "Peter Dimov" <pdimov@m...> wrote: >> >> You can use apply<> from <boost/bind/apply.hpp> instead of 'call': >> >> bind(apply<bool>(), bind(&widget::sig, &widget_a)) (); // should call >> widget_a->sig > > Thank you for the reply. > > I have changed the line to use apply<bool>() and included the header > file, but it won't compile complaining about noncopyable members of > the signal of the widget. Any ideas what that is all about ? Please change every 'F f' to 'F & f' in boost/bind/apply.hpp; this will take care of the problem. I've already updated the CVS version. The problem is that a signal is noncopyable and cannot be passed by value.

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Using Bind on Signals
by Darren Vincent Hart 30 May '03

30 May '03

I am building a widget set using the signals and slots library. I have the need to be able create a functor (FA) that receives another (FB) as an argument to its constructor. I will connect FA to the signal of a widget, when FA is run it will perform a test and execute FB if appropriate. I want to be able to use the signal member of another widget as FB, so I am trying to use bind to get that function object for the signal. I am experiencing two problems: 1) When the member functor (FB) is bound to the signal of another widget, the slots don't get called. (No error results, but the connected slot doesn't print anything so I am assuming it isn't being executed). 2) I can't get it to compile when the signal has a <bool ()> signature, I can only get it to compile with a <void ()> signature. I am trying to assign the result of bind to a boost::function<bool ()> but I get an error saying it can't make the conversion, what type should I be using if not boost::function (note that it works if the signal is void())? The following is a commented test_case demonstrating the problem. Any assistance in binding to signals and compiling those with a bool() signature would be greatly appreciated. Thanks in advance, Darren Hart compile with: g++ test.cpp -o test -lboost_signals // test.cpp ---------------------------------------------------------- #include <iostream> #include <boost/signal.hpp> #include <boost/function.hpp> #include <boost/bind.hpp> using namespace std; struct widget { boost::signal<bool ()> sig; boost::signal<bool (char)> keypress; bool test() { cout << "widget::test() - sig empty: " << (sig.empty() ? "true" : "false") << endl; sig(); return true; } }; template <typename T> struct handler { boost::function<T ()> slot_; handler(boost::function<T ()> slot) : slot_(slot) { } bool operator()(char letter) { cout << "handler::operator() - received a " << letter << endl; if (letter == 'A') { cout << "\texecuting slot\n\t"; slot_(); cout << endl; } return true; } }; struct no_op { bool operator()() { cout << "no_op::operator() - doing nothing" << endl; return true; } bool test() { cout << "no_op::test()" << endl; return true; } }; int main() { // instantiate two widgets widget widget_a; widget widget_b; /* The goal is to connect the hanlder to widget_b which will then call * widget_a's sig signal. The problem is that even though widget_a's * test says that sig() isn't empty, it doesn't execute when bound * directly in handler_b. It does however work when called as part * of the test() member function as in handler_c. We must get * handler_b to work in order to do this in libstk! We can't compile * at all if the signal returns a bool. */ // instanstiate the function objects no_op no_op_; // bind to a no_op member, successul handler<bool> handler_a( boost::bind(&no_op::test, &no_op_) ); // bind to a widget signal handler, BROKEN //handler<bool> handler_b( boost::bind<bool>(&widget::sig, &widget_a) ); // <-- Broken // bind to a widget member, successul handler<bool> handler_c( boost::bind(&widget::test, &widget_a) ); // connect the function objects to the widgets widget_a.sig.connect(no_op_); widget_b.keypress.connect(0, handler_a); //widget_b.keypress.connect(1, handler_b); // fix handler_b above, then uncomment this widget_b.keypress.connect(2, handler_c); cout << "attempting to bind to widget_a's sig signal" << endl; // store the function object returned by binding a widget signal, BROKEN //boost::function<bool ()> fp = boost::bind(&widget::sig, &widget_a); // <-- BROKEN // executre the functor returned by binding a widget signal, BROKEN // (builds, but doesn't really call widget_a.sig()) boost::bind(&widget::sig, &widget_a)(); // <-- Test if binding works at all, it doesn't // signal the keypress signals, they will test the character and execute their // slots if it equals 'A' cout << "signalling widget_b.keypress('B')" << endl; widget_b.keypress('B'); // call the handler 3 times, but never execute its slot cout << "***\nThis correctly executed the three handlers which, also correctly," << " do not execute their slots\n***" << endl; cout << "signalling widget_b.keypress('A')" << endl; widget_b.keypress('A'); // call the handler 3 times, executing the slot cout << "***\nThis executes the three handlers, but handler_b calls slot_() " << "and widget_a's signal does not execute the slot it has, which the " << "test() in handler_c successfully executes.\n***" << endl; return 0; } // --------------------------------------------------------------------

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RE: [Boost-Users] Regex: matching either of 2 fields, in any order
by john.wismar＠alldata.com 30 May '03

30 May '03

The detail I'm concerned about -- and it may not be a problem because I may be overlooking something -- is that the string I'm matching against can have zero or one 'C' field and zero or one 'O' fields. It looks like the "C(\\d+)|O(\\w+)" expression will match either of them if at least one is present, but after that, I would need optionally to match the other one. Matching the same field again would be an error. In other words: ~C12345~OF <-- valid (1 of each) ~OF <-- valid (1 'O' field) ~C12345 <-- valid (1 'C' field) ~ZAQ~C12345 <-- valid (1 'C' field) ~OV~C67890 <-- valid (1 of each) ~A23~OV~DFG~C67890~ZAQ <-- valid (1 of each) ~A23~DFG <-- valid (neither) ~C12345~OF~C67890 <-- invalid (2 'C' fields) ~C12345~OF~OV <-- invalid (2 'O' fields) ~ASD~C12345~OF~OV <-- invalid (2 'O' fields) Thanks again for your help!! ------------------------------ John Wismar BSA - AllData Offline Products john.wismar(a)alldata.com > -----Original Message----- > From: John Maddock [mailto:john_maddock@compuserve.com] > Sent: Friday, May 30, 2003 3:43 AM > To: Boost-Users(a)yahoogroups.com > Subject: Re: [Boost-Users] Regex: matching either of 2 > fields, in any order > > > > I can see how I could do this in a loop to replace the different > > subfields. Is there another step I would need to take to > guarantee that > > there is at most one of each type of subfield? > > Well if you search for "C(\\d+)|O(\\w+)" it can only match > one or the other > can't it? Or am I missing something? > > John.

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int64_t problem
by Sigis 30 May '03

30 May '03

Hi, I am using OpenInventor and boost 1.29 librariess. Both of them have defined int64_t: typedef __int64 int64_t; During compiling I get some errors: d:\work\projects\medint\dist\include\boost\cstdint.hpp(240) : error C2632: '__int64' followed by '__int64' is illegal d:\work\projects\medint\dist\include\boost\cstdint.hpp(240) : warning C4091: 'typedef ' : ignored on left of '__int64' when no variable is declared d:\work\projects\medint\dist\include\inttypes.h(75) : error C2632: '__int64' followed by '__int64' is illegal d:\work\projects\medint\dist\include\inttypes.h(75) : warning C4091: 'typedef ' : ignored on left of '__int64' when no variable is declared The only solution I found is to add #undef just before define at boost/cstdint.hpp: #undef int64_t typedef __int64 int64_t; But it looks as dirty solution. Maybe it is possilbe to solve this problme in more elegant way? P.S. adding #undef int64_t to boost/config/user.hpp only reduces the count of errors from 10 to 6. -- Sigis

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RE: [Boost-Users] newbie: trouble composing with boost::bind
by Tom Matelich 30 May '03

30 May '03

http://groups.yahoo.com/group/Boost-Users/message/4086 > -----Original Message----- > From: Jacques A. Vidrine [mailto:nectar/boost@celabo.org] > Sent: Wednesday, May 28, 2003 6:19 AM > To: boost-users(a)yahoogroups.com > Subject: [Boost-Users] newbie: trouble composing with boost::bind > > > [Apologies if this is a duplicate. I posted this shortly after I > subscribed, but I didn't see it come across.] > ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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RE: [Boost-Users] Regex: matching either of 2 fields, in any orde r
by Jim.Hyslop 30 May '03

30 May '03

John Maddock wrote: [unknown] wrote (please try to attribute quotes) > > I can see how I could do this in a loop to replace the different > > subfields. Is there another step I would need to take to > > guarantee that > > there is at most one of each type of subfield? > > Well if you search for "C(\\d+)|O(\\w+)" it can only match > one or the other > can't it? Or am I missing something? I could be wrong, but I interpreted the OP's question to mean: is it possible to have the regex generate an error if more than one sub-field of a specific type is found, i.e. the following would be invalid: ~C123~C345 The original poster can correct me if I've misinterpreted anything. -- Jim

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RE: [Boost-Users] Regex: matching either of 2 fields, in any order
by john.wismar＠alldata.com 30 May '03

30 May '03

> -----Original Message----- > From: John Maddock [mailto:john_maddock@compuserve.com] > Sent: Thursday, May 29, 2003 4:10 AM > To: Boost-Users(a)yahoogroups.com > Subject: Re: [Boost-Users] Regex: matching either of 2 > fields, in any order > > > Is it possible to do this in a single > > operation, given that the order of the fields is arbitrary? > > Yes do a conditional search and replace: > > search for "C(\\d+)|O(\\w+)" > > and replace with "(?1first-text)(?2second-text)" > > don't forget to set the flag format_all when calling > regex_merge to do this > (in future conditional replacements will only be enabled when actually > requested). Thanks for the reply! I can see how I could do this in a loop to replace the different subfields. Is there another step I would need to take to guarantee that there is at most one of each type of subfield? ------------------------------ John Wismar BSA - AllData Offline Products john.wismar(a)alldata.com

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Problems Using boost:date_time library
by Carl Waldbieser 29 May '03

29 May '03

I recently tried some simple tests of the Boost date-time library (Boost 1.30.0 MSVC6) and ran into problems. I don't have the original code in front of me (unfortunately I left it at work), but more or less, it looked like this: #include "boost/date_time/gregorian/gregorian.hpp" #include <iostream> int main() { using namespace boost::gregorian; date today = day_clock::local_day(); month_iterator it(today); std::advance(it, 3); std::string strDate(to_simple_string(*it)); std::cout << "New date is " << strDate << std::endl; return 0; } The first problem I ran into was that I got a linker error because the class greg_month (in greg_month.hpp) did not provide definitions for the following member functions: const char* as_short_string() const; const char* as_long_string() const; I quicky wrote some inline switch statements to get past that hurdle, but then the compiler started complaining when I tried to use std::advance. It is unfortunate that I do not have the exact error in front of me right now, but I did trace the problem to the definition of month_iterator. I found that if I derived its base implementation class from the class template iterator that it would compile without problems. Is this a problem with the STL that ships with MSVC6? Anyway, I was wondering if maybe there was something I had not set up correctly with my compiler that was causing me to get these errors. Any help would be appreciated. Carl Waldbieser waldbie(at-sign-goes-here)attglobal.net

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date_time generator question
by Claus Tondering 29 May '03

29 May '03

Is there any reason why date_time::partial_date<date> also exists as gregorian::partial_date, but date_time::first_kday_after<date> does not exist as gregorian::first_kday_after? (A similar question could be asked for other classes in the date_generators.hpp file.) -- Claus Tondering Danish Technological Institute

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