July 2007 - Boost-users - lists.boost.org

Boost.Test Documentation
by James Hamlin 17 Aug '07

17 Aug '07

Hi, I've begun using Boost.Test to construct test suites for a project, and it looks like it does a great job and is full of nice features (I really like the auto unit tests). But I have a big complaint: the documentation is pretty poor. I had a hard time getting a simple example off the ground, because it wasn't clear that I had to link to parts of the library. This was a surprise since most of Boost is templated and so is available entirely through the headers. I had to dig a bit to find the comment about the header that includes the main() code and other concrete functions. In addition, many of the examples are missing, and some of those that are available require the linking I mentioned but fail to note this, adding to my initial confusion. Lastly, the English grammar is very rough in parts, and while I understand that English may not be the primary language of the author, it can be a big hurdle to get started using the library when one has to grapple with the documentation to understand the intentions of the author. I don't mean to rant - the library is great, and I've already found it useful - but I'd love to get more out of it, and clean, clear, and thorough documentation will get me and others started with much less head scratching and frustration.<boost-test%20at%20emailaccount%20dot%20com%20%28please%20unobscure%29> Sincerely, James Hamlin Postscript: This is Boost-users, but I assume Gennadiy Rozental or somebody else with the knowledge and ability to update the documentation will see this message.

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Re: [Boost-users] cross compiling boost for ARM
by Hughes, James 12 Aug '07

12 Aug '07

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of remi > Sent: 05 January 2007 14:44 > To: boost-users(a)lists.boost.org > Subject: [Boost-users] cross compiling boost for ARM > > > hi! > > I want to cross compile boost for an ARM processor. > For a pxa 270. but when i try to cross compile boost with > arm-linux-g++ , it dosen't work ... a proble with jam... > > everyone can help me? > > Thank you > > BEST REGARDS > > Rémi bjam "-sGCC_ROOT_DIRECTORY=/opt/montavista/mobilinux/devkit/arm/iwmmxt_le" "-sGCC=iwmmxt_le-gcc" "-sGXX=iwmmxt_le-g++" <location for libs> Obviously you would need to change the location namd names of the compile tools to whatever you are using. James This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.

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shared_ptr, pimpl, reference semantics, and const correctness
by Braddock Gaskill 11 Aug '07

11 Aug '07

I am continuing work on a futures library for boost. future objects (as currently considered by the C++ standards committee, in particular Peter Dimov's proposal) have reference semantics, like many pimpl types. I have some burning questions about const correctness. Hypothetical reference-semantic example: future f1; future f2 = f1; //f2 refers to the same underlying object as f1 f2.set(42); //do something assert(f1.get() == 42); // see, same underlying object This is roughly equivalent to: boost::shared_ptr<future_impl> f1; boost::shared_ptr<future_impl> f2 = f1; A std::vector<T>::iterator is an example of another type with reference semantics. So, say I have a simple future class: class future_impl { public: bool get() const {return value_;} void set(bool value) {value_ = value;} private: bool value_; }; class future { //not really a future, just example public: future() : impl_(new future_impl) {} future(const future &other) : impl_(other.impl_) {} bool get() const {return impl_->get();} // Set may not be const, but it does NOT really modify this class void set(bool value) {impl_->set(value);} private: boost::shared_ptr<future_impl> impl_; }; I have made the future::set() method non-const, but it does NOT really modify the underlying future class, only the future_impl class it refers to. This makes life very difficult when it comes to passing futures by reference: // alternative #1 - pass const future & void f1(const future &f) { bool v = f.get(); // no problem, get() is const f.set(!v); // cannot do this, set() is not const // BUT I can bypass the const-ness trivially, so it is pointless future f2(f); f2.set(!v); } // alternative #2 - pass future & // with #2, I can't do simple things like this: // f2(future(f)); //ERROR: non-const reference from a temporary - irritating void f2(future &f) { bool v = f.get(); // no problem, get() is const f.set(!v); } // alternative #3 - pass by value // Constructing shared_ptr's is VERY inefficient void f3(future f) { bool v = f.get(); // no problem, get() is const f.set(!v); // cannot do this, set() is not const } // alternative #4 - const_future base class with the subset of const methods? // kinda like a const_iterator? seems klunky. class const_future {bool get() const;}; class future : public const_future {void set(bool);} Does anyone have any advice or ideas? Oh, and then there is a possible need for something like a weak_ptr<future_impl>, like a weak_future class? And then a const_weak_future? I don't want to think about it... Thanks, Braddock Gaskill

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Installer for Boost 1.34.1
by Rusty Jones 11 Aug '07

11 Aug '07

Hi, Does anyone know if boost consulting is going to provide an installer for 1.34.1 and if so what time frame? Cheers, Rusty

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Visual Studio 2005 ptr_list visualizer?
by Michael Marcin 10 Aug '07

10 Aug '07

Hello I've seen Visual Studio 2005 visualizers for various boost containers on here before. Has anyone written one for ptr_list that they can share? Thanks, Michael Marcin

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[Serialization] Problem serialization of derived classes
by Andreas Willich 09 Aug '07

09 Aug '07

Hi there! I have a problem with the code in the attachment. I followed the documentation and the examples, but I did not get the code to work. Gcc produces a lot of failures that something is already instantiated in header files of the serialization library. Has someone a idea what I am doing wrong? My gcc version is 4.1.1-r3 and I am working on a gentoo x86 box. Andreas Willich

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[program_options] patch - optional argument support (gnu getopt_long style)
by Bryan Green 08 Aug '07

08 Aug '07

Attached is a patch to program_options that implements optional argument support, in the style of GNU getopt_long. It adds one new method to 'value_type': 'implicit_value()'. The idea is that, if the option is given without an argument, it is assigned an "implicit" value. Otherwise, if the long-option is given an explicit argument via the equals sign (--arg=value), or the short-option is given an adjacent argument (-avalue), the explicit value will override the implicit one. For example: desc.add_options() ("proxy,p", value<int>(&proxy_port)->implicit_value(DefaultProxyPort), "run proxy service") ; ... if (vm.count("proxy")) enable_the_proxy(proxy_port); ./prog --proxy --opt2 --opt3 -> enables proxy on default port. ./prog --proxy=9000 --opt2 --opt3 -> enables proxy on port 9000. ./prog --opt2 --opt3 -> does not enable the proxy. -Bryan

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order of iterators in multi_index container
by boost＠larroy.com 07 Aug '07

07 Aug '07

Hi I was using multi_index nicely and then I wondered that although iterators are not invalidated when calling replace or modify, could it be that if I'm modifying inside a loop then incrementing the iterator no longer makes it iterate through all elements because of the index reordering? Regards. -- Pedro Larroy Tovar Promax R&D Lab

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[Important] Boost Subversion repository is now online
by Douglas Gregor 03 Aug '07

03 Aug '07

Hello all, The Boost Subversion repository is now back online. All of the files in CVS (including their histories) have been imported into the Subversion repository. CVS is still available for anonymous, read- only access for now, but will not be updated. The main Boost development branch is available via anonymous, read- only checkout at: http://svn.boost.org/svn/boost/trunk/ Or for developer read/write access at: https://svn.boost.org/svn/boost/trunk/ Information about accessing the Boost Subversion repository is available at: http://svn.boost.org/trac/boost/wiki/BoostSubversion Please report any problems to me to the main Boost list, and we will try to resolve them as quickly as possible. We still need help porting the regression-testing script over to use Subversion. See Trac ticket #1122: http://svn.boost.org/trac/boost/ticket/1122 Also, there is more documentation that will need to be updated within the Boost tree. - Doug Subversion tip: when you commit a change to Subversion that fixes ticket number NNN, include the text "Fixes #NNN" in your commit log. Trac will automatically close the ticket and cross-reference the commit with the ticket. See, for example, http://svn.boost.org/trac/ boost/changeset/38330

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newbie: boost::filesystem problems
by Eduard Diner 02 Aug '07

02 Aug '07

Hi, I want to use the filesystem library. For simplicity I first tried to compile the simple_ls.cpp (provided at: http://www.boost.org/libs/filesystem/doc/index.htm) Unfortunately I get lots of compiler-errors. For example the line 22: >> fs::path full_path( fs::initial_path<fs::path>() ); splitARFF.cpp:22: error: expected primary-expression before '>' token splitARFF.cpp:22: error: expected primary-expression before ')' token Does anyone have an idea how to solve the problem? THANKS The Makefile I used: ------------- OBJ = splitARFF.o CC = g++ SRC = $(OBJ:%.o=%.cpp) HDR = $(OBJ:%.o=%.h) LDFLAGS = -Wall -pg CFLAGS = -g -pg all: boostARFF boostARFF: splitARFF.o $(CC) $(LDFLAGS) $(OBJ) $(LIBS) -L/usr/lib -lboost_filesystem %.o: %.cpp $(CC) -c $(CFLAGS) $(SRC) -I/usr/include -------------

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