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[MSM] multiple visitors / signatures, and visitors by ref in submachines
by Albert Gil Moreno 06 Apr '12

06 Apr '12

Hi, I think that the visitors and the flags ideas of the MSM are very generic and easy to use. So, great! But, there is a way to define multiple visitors for a single state (base)? I think that it is not possible because the visitors mechanism is based on a "simple/single typedef" and not on an "listed typedef"... isn't it? So, why the visitors are not like flags? I mean, why not to use an "accept_sig_list" instead of a single "accept_sig"? Why is not possible a code like the following: struct my_visitable_state { typedef mpl::vector< args<void, VisitorType1&>, args<void, VisitorType2&> > accept_sig_list; void accept(VisitorType1&) const {} void accept(VisitorType2&) const {} }; By the way... I think that the usage of boost::ref() is not propagated to the submachines...? I've found that when my state machine is also in a submachine, the visitor of the state machine is passed by reference, but the submachine is passed always by value... is this a bug? (just using a pointer solved my needs, so just to report...) Thanks, Albert

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[MSM] state transitions and exceptions
by Stephan Menzel 06 Apr '12

06 Apr '12

Everyone, I did just get around to give the MSM a first shot and I have say I am impressed at the neat design, the ease of use, "understandability", tutorial ... exceptional work. Really great and it helped me a great deal so far. So thanks a bunch for this teriffic addition to boost. That's the kind of stuff I love boost for. There is one question however that puzzles me. How can / do I prevent state transistions when a transition function throws? Most transition functions are defined like that: void so_transition(event::Cause const &e) { methodCausingAnException(); } The tutorial only mentions this at the very end of the back-end docs and this is not clear to me. I have stuff inside my transitions that may throw and the example text mentiones other valid examples (like connect() logic). So what am I supposed to do here? This? void so_transition(event::Cause const &e) { try { methodCausingAnException(); } catch (const std::exception &sex) { return ??? } } The type is void and I can't return anything that would prevent the transition. Or should I just let the exception pass? What is the correct way? Suggestions are appreciated, Stephan

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[graph] Problem with vertex initialization in boost::add_vertex()
by Philipp Klaus Krause 06 Apr '12

06 Apr '12

I have graph as follows: struct cfg_node { iCode *ic; operand_map_t operands; std::set<var_t> alive; std::set<var_t> dying; }; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, cfg_node> cfg_t; And a fragment of code: wassertl (!boost::num_vertices(cfg), "CFG non-empty before creation."); for (ic = start_ic, i = 0, j = 0; ic; ic = ic->next, i++) { boost::add_vertex(cfg); wassertl (cfg[i].alive.empty(), "Alive set non-empty upon creation."); Nothing inside the loop add or deletes vertices or changes the alive members. The code works fine on Linux, but I got bug reports from Windows users. For them the assertion in the loop triggers (and an attempt to insert something into alive later segfaults). So I have two questions: What could be the cause of this problem? Has it been encountered before? Is the approach of using cfg[i] to get the vertex still correct? I've used this for some time, but I can't find it in current boost documentation. Philipp

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Asio SSL & short read error
by Jason Nye 05 Apr '12

05 Apr '12

Hi all, I've run into a strange problem with reading data using an SSL socket stream (client-side). The code we've got essentially does the following on each read: system::error_code ec; auto result = _source->read_some(buffer(buf, n), ec); // buf and n are defined as char* and size_t. // here is where the occasional strangeness occurs. I understand that during any streaming operation may return fewer bytes than requested - this is something we handle gracefully. However occasionally after read_some() above, we may get 0 bytes read and ec set to an internal ssl error code indicating a "short read". My understanding is that this particular error is benign and the software should just continue to try reading. In fact, when I change our code to deal with this error specifically and just continue reading, everything works nicely. The part I don't feel comfortable with is that it doesn't seem clear at all how to differentiate this particular error from a potentially fatal error other than comparing the error code's lower 8 bits against SSL_R_SHORT_READ (which I found by browsing the asio code and it is an OpenSSL constant). There doesn't seem to be any publicly facing constant that helps determine this situation. Here is the basic logic for how we handle this specifically (which I do not like at all because it puts SSL-specific error handling logic where it doesn't belong): // Loosely C++ code: if (result == 0) { if (EOF) { // Okay, end of the stream } else if (ec) { if ((ec.value() & 0xff) == SSL_R_SHORT_READ) { // Not a big deal - just retry the operation. } else { // Throw! } } } One other thing of interest is that the client-side code is using asio in a rather synchronous manner. I am not sure if this problem arises when using asio asynchronously. Is this the only way to handle this situation reliably? Did I miss something obvious? Thanks in advance, Jason. ______________________________________________________________________________________________ [cid:image003.png@01CD1352.4ED8A7C0] Jason Nye | Principal Software Engineer 5850 Opus Parkway, Suite 300 l Minnetonka, MN 55343 952.487.9693 l 866.433.4624 l www.vitalimages.com<http://www.vitalimages.com/> A Toshiba Medical Systems Group Company ______________________________________________________________________________________________

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Boost Library : Resource Requirements
by Santhosh Edukulla 05 Apr '12

05 Apr '12

Hi Users, We are first time users of Boost. As such our production environment is already constrained with resources, iam basically trying to collect few metrics for boost packages installation and usage sizing requirements. I learnt that it depends upon specific libraries we select. But, with all your usage and experience, any data ( quantified) to be shared with is really appreciated! Thanks in Advance! Santhosh

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Question regarding library testing system
by Robert Ramey 05 Apr '12

05 Apr '12

a) http://www.boost.org/development/running_regression_tests.html tells me how to run the test suite on ALL the libraries locally. How do I run the test suite on ONE particular library locally? b) I noticed that on the test page for the serialization library there are a number of boxes in dark green indicating - expected failures. I remember that there was a procedure for specifying expected failures but now I can't find it. Could someone point me to the relevant page? Robert Ramey

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[Asio] How to link library in Qt creator
by vahid r 05 Apr '12

05 Apr '12

Hello . I want to include boost.asio in my project created in Qt creator . what should I insert to my .pro file ? Qt 4.7.4(32 bit) - Qt Creator 2.3.0 - MinGW 4.4 boost 1.49.0 platform : Windows 7

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OpenVMS Build
by Victor Kirk 05 Apr '12

05 Apr '12

Hi, Apologies to anyone receiving/reading this for the second time, I originally sent this to the wrong list. I'm hoping to port an application to open vms using HP C++7.3. I don't suppose anyone has any dcl scripts to build boost. I 'only' need asio and threading. Currently I'm just trying to compile the asio chat examples. I'm completely new to VMS and the compiler, I managed to get a few things to compile but now get a "could not open source file "sys/select.h"', a bit of googling suggests I may need to have an HP porting library installed or maybe I'm just missing an prepocessor directive to include the correct code, can't see anything obvious in socket_types.hpp to set? Any pointers in the right general direction would be gratefully appreciated. Kind Regards, Vic -- Victor Kirk Analyst Transportation Systems - Network Services Serco Civil Government Cavendish House Clearwater Park Prince's Wharf Stockton-On-Tees TS17 6QY T +44 (0) 1642 636 894 F +44 (0) 1642 636 701 Victor.Kirk(a)serco.com<mailto:user.name@serco.com> www.serco.com<http://www.serco.com> [cid:image001.gif@01CD1271.9BF065C0]<http://www.serco.com/> This e-mail and any attachments are for the intended addressee(s) only and may contain confidential and/or privileged material. If you are not a named addressee, do not use, retain or disclose such information. This email is not guaranteed to be free from viruses and does not bind Serco in any contract or obligation. Serco Limited. Registered in England and Wales. No: 242246 Registered Office: Serco House,16 Bartley Wood Business Park, Hook, Hampshire RG27 9UY United Kingdom.

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File-system persistence for boost shared memory files
by Rajalakshmi Iyer 05 Apr '12

05 Apr '12

Hello, The boost documentation suggests that shared memory interprocess mechanism can have file-system or kernel persistence. When I create shared memory files on an Ubuntu Linux host, they are created at /var/run/shm. But on a system reboot, the shared memory files go away, which means they are using kernel persistence. How can I ensure that shared memory files persist across reboots? Thanks! -- Twitter: @Blismobile <http://twitter.com/#!/blismobile> BlisMobile Media 32 Percy Street, London W1T 2DE www.blismobile.com [image: BlisMobile] <http://www.blismobile.com/>[image: Follow on Twitter]<http://twitter.com/#!/blismobile>[image: Blis Website] <http://www.blismobile.com/> This communication is from BlisMobile Media, which is a trading name of Breeze Tech (UK) Ltd, a company registered in England and Wales with registered number 06455773. Its registered office is 32 Percy Street, London W1T 2DE, United Kingdom. This communication contains information that is confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). If you are not the intended recipient(s), please (1) notify info(a)blismobile.com by forwarding this email and delete all copies from your system and (2) note that disclosure, distribution, copying or use of this communication is strictly prohibited. Email communications cannot be guaranteed to be secure or free from error or viruses. All emails sent to or from a Blismobile email account are securely archived and stored by an external supplier. This email does not constitute a contractual agreement; such agreements are in specified contractual or Insertion Order (IO) form only and exclusively contain all the terms to which Breeze Tech )UK) Ltd will be bound. To the extent permitted by law, Breeze Tech (UK) Ltd does not accept any liability for use of or reliance on the contents of this email by any person save by the intended recipient(s) to the extent agreed in a contract or Insertion Order. Opinions, conclusions and other information in this email which have not been delivered by way of the business of Breeze Tech (UK) Ltd are neither given nor endorsed by it.

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Getting Position from result of "boost::make_split_iterator(s1, token_finder(is_any_of(s2), token_compress_on)); "
by asif saeed 05 Apr '12

05 Apr '12

Hi, Can I get the position from the iterator that I get from split_iterator? The position I am seeking to determine is the "zero-based number of token separated by the separator". That is, in "one;two;three;four;five;six;seven;eight", the position of three is 2 and eight is 7. Can anyone help me on this? I am using Boost 1.47.0 on Windows 2003 Standard Edition 32-bit with Visual C++ 2010 Express. Best regards, Asif

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