- Boost-users - lists.boost.org

[Boost users] MacPorts and Boost path issues
by John Burgoon 17 Mar '09

17 Mar '09

I am a command-line user of C++ and boost. I installed boost on Mac Leopard using mac ports like this: sudo port install boost I saw as it installed that macports was using bjam, and the version was 1.37. I want to use boost/regex.hpp, so I know it's not just a matter of including a header file. When I compile my own source files, I see a variety of paths, such as /opt/local/var/macports/sources/rsync.macports.org/release/ports/devel/boost /opt/local/var/macports/sources/ rsync.macports.org/release/ports/devel/boost/files etc My first question is, when I compile my work on command line using g++: i.e., g++ myfile.cpp -o myfile which of these paths should I include? I think I am supposed to do something like g++ -I /path/to/boost myfile.cpp -o myfile but I do not understand how a person knows which dir to use. Another way of asking this is: If YOU sat down at my machine and decided to use boost, what would you do to a)find it and b)include it in your pre-processor includes? Is there clear documentation on how a fellow figures out where the install is located, and then shows how to include it? Perhaps I simply don't know what to ask for, but when I google for this I gfind a zillion unrelated things. Do I in fact need to do the "-I /silly/long/path/to/the/bowels/of/the/machine/where/macports/hid/buried/installed/boost" every single time I compile something?? It occured to me to try a soft link somewhere in my development dir to save typing, but in order to do that of course I first need to figure out where boost actually resides in the system. I also have fink installed on the system, and fink says that boost1.33 is installed. So how in the world do I update fink to accept a later version? When I try to update, fink says no update is needed. Thanks in advance for the hand-holding. Boost is worth the effort to figure it out, yes? -- John Burgoon Development Staff, GiveALink.org Informatics 304 812-856-1833 office 812-391-2428 cell -- >>Insight without implementation is worthless. Get to work.

2 1

problems with boost::spirit
by Goran 17 Mar '09

17 Mar '09

Hi all, I wanna get boost::spirit to tell me which position in my string is liable that parsing fails. Here's a fully compiling demonstration: #-------------------------------------------------------------------- #include <iostream> #include <string> #include <boost/spirit.hpp> using namespace std; using namespace boost::spirit; int main() { string s = "#x"; rule<> r = chlit<>('#') >> chlit<>('X') >> *space_p; parse_info<> p = parse(s.c_str(),r); if(p.full) cout << "File is OK:\n"; else cout << "Error at pos " << p.length << ".\n"; return 0; } #-------------------------------------------------------------------- With this I get: Error at pos 4294967295. But if "string s = "#Xx" I get: Error at pos 2. This is what I want. But why do I get 4294967295 which is 2^32-1. Thanks for any comments, Goran.

2 1

ASIO certificate help.
by Mohammed Rasmy 16 Mar '09

16 Mar '09

1 0

mutex types and interprocess documentation question
by Archie14 16 Mar '09

16 Mar '09

Boost documention has following code in the paragraph "Scoped lock" (reference to the paragraph is here.../html/interprocess/synchronization_mechanisms.html#interprocess.synchron ization_mechanisms.mutexes) using namespace boost::interprocess; //Let's create any mutex type: MutexType mutex; ... I did not find a reference to available types declarations. Paragraph above "Scoped lock" talks about mutex types, but I did not find type declarations. My question is: where are available types declared? I will also appreciate the example of such declaration that shows what #include should be used.

2 2

another metaprogramming question
by Noah Roberts 16 Mar '09

16 Mar '09

This seems to me like it should work. Yet the check() call resolves, without error, to the first one...which should cause an error and trigger SFINAE. Can anyone help me figure out what gives? Compiler is MSVC++ 8. Normally the SFINAE stuff works so I'm betting on my mistake this time. Basically I need to check it the metafunction meta<T> returns something. If it does then the object is a record. If it doesn't then it is not. #include <iostream> #include <boost/mpl/transform.hpp> #include <boost/mpl/placeholders.hpp> #include <boost/mpl/vector.hpp> template < typename T1, typename T2 > struct construct_metafield_composed { typedef T1 type; // Not what the real one does. }; template < typename RECORD > struct meta { struct type : boost::mpl::transform < typename RECORD::fields , construct_metafield_composed < RECORD , boost::mpl::placeholders::_1 > >::type { typedef RECORD meta_for; }; }; template < typename T > struct is_record_check { typedef char (&no) [1]; typedef char (&yes) [2]; template < typename S > static yes check(typename meta<S>::type *); template < typename S > static no check(...); enum { value = sizeof(check<T>(0)) == sizeof(yes) }; typedef boost::mpl::bool_<value> type; }; struct test { typedef boost::mpl::vector< int, double > fields; }; int main() { // output is 1\n1\n. std::cout << is_record_check<test>::value << std::endl; std::cout << is_record_check<int>::value << std::endl; // meta<int>::type x; - yet this will cause compilation error. std::cin.get(); }

2 2

gcc optimization and boost::any
by John 16 Mar '09

16 Mar '09

Is anyone aware of a bug/quirk in boost::any that is exposed by GCC optimization? (Or vice versa: a bug in GCC optimization exposed by boost::any)? We've got a particularly insidious runtime bug that appears under `-O2` with gcc version 4.2.2, but not with gcc 3.3.3, and not with gcc 4.3.3. We narrowed it down to a single .cpp file, which contains a single method, which does nothing but call boost::any_cast several times to extract a pointer from a boost::any instance. By compiling this file under -O2, (gcc version 4.2.2) we can cause the bug. By compiling without any `-O` flags, the bug does not appear. (boost version 1_34_1). We're working to identify a minimal test case that we can post here. We still haven't pinpointed the exact cause. To be clear, we're not 100% sure the bug is in boost::any or gcc -- it merely appears to be so since changing compiler flags or compiler versions makes the bug disappear. If you know of such a bug or quirk in either GCC or boost::any, or of a write-up of this somewhere... or even some idle speculation... it could save us a lot of time tracking this down. Thanks, -John

3 3

Interprocess general questions
by Andrej van der Zee 16 Mar '09

16 Mar '09

Hi, I am using Boost.interprocess for the first time and read the documentation. It is difficult for me to decide what construct would best fit my scheme, because of all the options. I hope that somebody could help me find out. I am using Boost 1.38 on Ubuntu 8.10. In my setup, I have one parent process that forks many (could be hundreds) child processes. In the parent process I need to maintain a data-queue. The child processes insert data into the queue and once every X seconds the parent removes all messages from the queue (in order to dump it to a database). The data is one type only and fixed length: A struct with a few doubles, a few integers and a fixed-length string. Because there can be hundreds of child processes that insert into the data-queue many times a second, I guess it would make sense to have multiple data regions in one big shared memory segment, each with it's own synchronization mechanism? I mean, it is important that the child processes are able to insert the data fast and do not suffer lock contention too much (a "little" overhead is fine though). So my question is what components from the Boost.interprocess-library should I use? Any other comments and/or tips before I start coding? Thank you! Andrej van der Zee

1 0

installing boost in linux (help needed urgently) !!!!!!
by ayan sinha 15 Mar '09

15 Mar '09

Hi, I am new to linux and also to boost library.. I am planning to install boost library in linux box (which is a production machine with no net connectivity). i have already got the linux version of boost in that machine and now I am planning to install it. Can please somebody tell me what are the steps needs to be done to install linux.. with commands (I cant use any tool that boost provide to install because ther is no net connectivity in that box). I have gone through the boost website .. but it looks very complicated :) also I have gone through couple of websites but it was not much usefull. I will be really greatfull if somebody can tell me what are the steps (with commands) to install in linux box. Thanks in Advance, Ayan.

5 5

Why "Mixing a dll boost library with a static runtime is a really bad idea..."?
by D M 15 Mar '09

15 Mar '09

Hi, I want (need) to use boost libs as dll with a static run-time library. In this case auto_link.hpp gives me an error "Mixing a dll boost library with a static runtime is a really bad idea...". Why is it a bad idea? I don't think that it's a good idea but requirements in our project demand static-runtime linkage for all modules and they don't want to use regex as static library cause of it's size. What problems could it cause? I know only one problem with a memory allocation in different modules. Any more? Thanks, Vladimir

3 3

Re: [Boost-users] proto: analytical-only math functions
by Hicham Mouline 14 Mar '09

14 Mar '09

> ----- Original Message ----- > From: peter_foelsche(a)agilent.com > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] proto: analytical-only math functions > Date: Fri, 6 Mar 2009 12:40:22 -0700 > > > Could the originator of this thread try to explain to me what he wants to > accomplish? > I still cannot figure any use case for proto. > > Peter Step1 is to have a derivative metafunction which computers the nth derivative of a function at compile time. In order to do that, I need a mathematical language to write my functions. so I have constants, variables, basic_functions and user-defined functions that are terminals of my language f(x) = log(x); g(x) = derivative(1, f, x); g(x) will be 1/x; I should manage to run derivative purely in compile time. Later, I will look at stochastic and partial differential equations and write functions to solve them analytically whenever possible... proto will help me define terminals, the grammars for what are acceptable expressions. regards,

2 6