December 2002 - Boost-users

shared_ptr does not call destructor
by Ani Taggu 15 Dec '02

15 Dec '02

Hi: I am using windows 2000 with VC 6.0 and boost 1.28. In my project, I have an array of pointers to objects: class foo { public: ~foo() {} private: std::vector<boost::shared_ptr<MyType> > myArr_; }; I found that the destructor for MyType is never called. Printing the shared_ptr::use_count = 6 at ~foo() above. Any suggestions on what could be happening and how to approach the debugging? Thanks, -Ani

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Test Library: Program Execution Monitor output
by klapshin <klapshin＠yahoo.com> 13 Dec '02

13 Dec '02

Hello, I just plugged program execution monitor in my code and there are certain things I don't really like. First of all is not it odd to see a contradictory messages like: --------------------------- no errors detected **** error return code 1 ********** errors detected; see standard output for details *********** --------------------------- I don't really need this "no errors detected" message. Looking into code I found a way to turn it off -- I have to define an environment variable. I have a way to control this behavior. This is good. Bad news though that the way to control is quite an awkward one. I would like to have some internal control, probably overwritable via environment variable. Another concern is that I have no control on return codes in case of exceptions and runtime errors. For instance in my company all programs have to return 1 in case of failure (and 0 on success). Other return codes are no-no. I am sure there are zillions of different environments with different, often contradictory requirements for error handling. The point I am trying to make is that it is not that difficult to make Monitor more flexible, and it will increase its value tremendously. The ultimate solution would be giving user an opportunity to supply error-handling function which will print out whatever it want to, and return desired return code. Best regards, Kirill Lapshin

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weak_ptr and threads
by Duane Murphy 12 Dec '02

12 Dec '02

The application I am working on uses a number of threads to do work. In some cases pointers from one thread (usually the "main" thread) are passed to a worker thread. The worker thread will use this pointer to handle processing of the results (in various ways). The problem that I am concerned about is lifetime control. Objects in the main thread could be deleted before the worker thread has a chance to use them. This of course would be a "bad thing." I am considering investigating the use of weak_ptr as a potential solution to this problem. The basic idea would be to pass weak_ptr's to the worker thread. The worker thread can then check the validity of the weak_ptr before accessing it. Can weak_ptr be used without using shared_ptr? It seems like they are closely tied. I was hoping to use weak_ptr without forcing the use of shared_ptr. Are there other solutions to this problem, besides the obvious "Dont let it happen." :-) [ Note that we are not yet using boost::threads so this is a more general question about managing inter-thread object lifetimes. ] Thanks for your tips and suggestions, ...Duane

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weak_ptr and threads
by Duane Murphy 12 Dec '02

12 Dec '02

The application I am working on uses a number of threads to do work. In some cases pointers from one thread (usually the "main" thread) are passed to a worker thread. The worker thread will use this pointer to handle processing of the results (in various ways). The problem that I am concerned about is lifetime control. Objects in the main thread could be deleted before the worker thread has a chance to use them. This of course would be a "bad thing." I am considering investigating the use of weak_ptr as a potential solution to this problem. The basic idea would be to pass weak_ptr's to the worker thread. The worker thread can then check the validity of the weak_ptr before accessing it. Can weak_ptr be used without using shared_ptr? It seems like they are closely tied. I was hoping to use weak_ptr without forcing the use of shared_ptr. Are there other solutions to this problem, besides the obvious "Dont let it happen." :-) [ Note that we are not yet using boost::threads so this is a more general question about managing inter-thread object lifetimes. ] Thanks for your tips and suggestions, ...Duane

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uBLAS and fast matrix multiplication
by klapshin <klapshin＠yahoo.com> 12 Dec '02

12 Dec '02

Hello, I am considering switching from in-house matrix implementation to uBLAS. Overall impression from uBLAS is quite good, but it seems that uBLAS does not take advantage of fast matrix multiplication algorithms such as Strassen or Vinograd. Is that correct? If yes, are there plans to implement such algorithms? Best regards, Kirill Lapshin.

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Re: [Boost-Users] testing if shared_ptr has been assigned
by dick.bridges＠tais.com 12 Dec '02

12 Dec '02

I should point out that I went 'back' to get() because I got tired of explaining the 'correct' way [ie, if( b ) ] Darin Adler provided in his answer. |---------+----------------------------------------------------> | | Dick | | | Bridges/CSE/IRV/CONTRACTOR/TOSHIBA-TAIS@T| | | OSHIBA-TAIS | | | | | | 12/12/2002 08:07 AM | | | Please respond to Boost-Users | | | | |---------+----------------------------------------------------> >----------------------------------------------------------------------------------------------| | | | To: Boost-Users(a)yahoogroups.com | | cc: | | Subject: Re: [Boost-Users] testing if shared_ptr has been assigned | >----------------------------------------------------------------------------------------------| >From the docs: <snippet> get T * get() const; // never throws Returns: the stored pointer. Throws: nothing. </snippet> Therefore you can use if( b.get() ) or if( b.get() == NULL ) "TEA Hartmann, Steven" To: boost-users(a)yahoogroups.com <SHartmann(a)aus.t cc: elusa.com> Subject: [Boost-Users] testing if shared_ptr has been assigned 12/11/2002 11:01 AM Please respond to Boost-Users I need some help in testing for the condition of whether a shared_ptr has been assigned. In the following example, the "if( b != NULL ) does not work. How would I do this test? typedef boost::shared_ptr<int> IPtr; int i( 0 ); IPtr a( i ); IPtr b; if( some condition ) b = a; if( b != NULL ) { // How should this really be coded? } Best Regards, Steve [Non-text portions of this message have been removed] 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/ 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] Test Library: Program Execution Monitor output
by Tom Matelich 12 Dec '02

12 Dec '02

> I don't really need this "no errors detected" message. Looking into > code I found a way to turn it off -- I have to define an environment > variable. > I have a way to control this behavior. This is good. Bad news though > that the way to control is quite an awkward one. I would like to > have some internal control, probably overwritable via environment > variable. In case you hadn't though of this workaround: if(getenv("VAR") == 0) putenv("VAR=defaultvalue"); Not to say a programmatic method is not worthwhile. ----------------------------------------------------------------------- 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] testing if shared_ptr has been assigned
by TEA Hartmann, Steven 12 Dec '02

12 Dec '02

Thanks all. That works beautifully. -----Original Message----- From: Tom Matelich [mailto:tmatelich@zetec.com] Sent: Thursday, December 12, 2002 12:25 AM To: 'Boost-Users(a)yahoogroups.com' Subject: RE: [Boost-Users] testing if shared_ptr has been assigned if(b) should do it. shared_ptr has an implicit conversion to bool (sort of). > -----Original Message----- > From: TEA Hartmann, Steven [mailto:SHartmann@aus.telusa.com] > Sent: Wednesday, December 11, 2002 11:02 AM > To: boost-users(a)yahoogroups.com > Subject: [Boost-Users] testing if shared_ptr has been assigned > > > I need some help in testing for the condition of whether a > shared_ptr has > been assigned. In the following example, the "if( b != NULL > ) does not > work. How would I do this test? > > typedef boost::shared_ptr<int> IPtr; > > int i( 0 ); > IPtr a( i ); > IPtr b; > > if( some condition ) > b = a; > > if( b != NULL ) { // How should this really be coded? > } > > > Best Regards, > > Steve > > > [Non-text portions of this message have been removed] > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Get 128 Bit SSL Encryption! > http://us.click.yahoo.com/CBxunD/vN2EAA/xGHJAA/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/ > > ----------------------------------------------------------------------- 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. ----------------------------------------------------------------------- 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/ [Non-text portions of this message have been removed]

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Re: [Boost-Users] testing if shared_ptr has been assigned
by dick.bridges＠tais.com 12 Dec '02

12 Dec '02

>From the docs: <snippet> get T * get() const; // never throws Returns: the stored pointer. Throws: nothing. </snippet> Therefore you can use if( b.get() ) or if( b.get() == NULL ) "TEA Hartmann, Steven" To: boost-users(a)yahoogroups.com <SHartmann(a)aus.t cc: elusa.com> Subject: [Boost-Users] testing if shared_ptr has been assigned 12/11/2002 11:01 AM Please respond to Boost-Users I need some help in testing for the condition of whether a shared_ptr has been assigned. In the following example, the "if( b != NULL ) does not work. How would I do this test? typedef boost::shared_ptr<int> IPtr; int i( 0 ); IPtr a( i ); IPtr b; if( some condition ) b = a; if( b != NULL ) { // How should this really be coded? } Best Regards, Steve [Non-text portions of this message have been removed] 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] testing if shared_ptr has been assigned
by Tom Matelich 12 Dec '02

12 Dec '02

if(b) should do it. shared_ptr has an implicit conversion to bool (sort of). > -----Original Message----- > From: TEA Hartmann, Steven [mailto:SHartmann@aus.telusa.com] > Sent: Wednesday, December 11, 2002 11:02 AM > To: boost-users(a)yahoogroups.com > Subject: [Boost-Users] testing if shared_ptr has been assigned > > > I need some help in testing for the condition of whether a > shared_ptr has > been assigned. In the following example, the "if( b != NULL > ) does not > work. How would I do this test? > > typedef boost::shared_ptr<int> IPtr; > > int i( 0 ); > IPtr a( i ); > IPtr b; > > if( some condition ) > b = a; > > if( b != NULL ) { // How should this really be coded? > } > > > Best Regards, > > Steve > > > [Non-text portions of this message have been removed] > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Get 128 Bit SSL Encryption! > http://us.click.yahoo.com/CBxunD/vN2EAA/xGHJAA/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/ > > ----------------------------------------------------------------------- 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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