April 2006 - Boost-users - lists.preview.boost.org

Converting epoch(long) to ptime in Boost.Date_Time
by gdprosch＠micron.com 23 Aug '06

23 Aug '06

I would like to convert epoch(long) time values to boost ptime and vice versa. On the surface this seems relatively easy but some of the functions needed are missing and there is an issue ensuring that the local time is properly applied. Has someone come up with an easy way to do this? I can convert to ptime like this... long epoch_in = 1140411002; // 2006-Feb-19 21:50:02 std::time_t stdtime ( epoch_in ); ptime = from_time_t( stdtime ); To convert from ptime back to epoch(long) there is no conversion provided the other way. I found some code the author supplied a few years ago here: http://lists.boost.org/MailArchives/boost-users/msg07254.php Unfortunately, the result does not correctly apply local time. The following code... std::time_t to_time_t(ptime t) { ptime start(gregorian::date(1970,1,1),time_duration(0,0,0)); return (t-start).total_seconds(); } ... produces a date with the value: 2006-Feb-20 04:50:02 and not 2006-Feb-19 21:50:02 (I am in US MST). I've played around with applying the local offset but I end up with a lot of lines of code that leave me wondering if there is a better way. It would be nice if it were simple like this (assuming local time adjustment is correctly applied)... long epoch_in = 1140411002; // 2006-Feb-19 21:50:02 ptime pt = from_epoch( epoch_in ); long epoch_out = to_epoch( pt ); Many thanks, > Greg Prosch > Micron Technology, Inc.

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Building boost for 64-bit on AIX
by Patrik Jonsson 17 Aug '06

17 Aug '06

Hi, I'm trying to build boost (1.32.0) on an IBM SP2 under AIX5, using the 64-bit ABI. This is troublesome. I do: bjam "-sTOOLS=gcc" "-sGXX=g++ -maix64 -pthread" --prefix=$HOME --libdir=$HOME/lib64-gcc --includedir=$HOME/include-gcc install But it doesn't work. I get loads of errors like: gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so ld: 0711-738 ERROR: Input file bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o: XCOFF32 object files are not allowed in 64-bit mode. collect2: ld returned 8 exit status set -e LIBPATH=bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true:$LIBPATH export LIBPATH "g++" -maix64 -pthread -g -fPIC -shared -o "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_month.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/greg_weekday.o" "bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/date_generators.o" ...failed gcc-Link-action bin/boost/libs/date_time/build/libboost_date_time.so/gcc/debug/shared-linkable-true/libboost_date_time-gcc-d-1_32.so... ...skipped <@boost!lib64-gcc>libboost_date_time-gcc-d-1_32.so for lack of <@boost!libs!date_time!build/libboost_date_time.so/gcc/debug/shared-linkable-true>libboost_date_time-gcc-d-1_32.so... It seems it's using -maix64 ok when trying to build the library, but not when compiling... Can anyone tell me what the proper way of building boost under these conditions are? Thanks, /Patrik Jonsson

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[Variant] Time complexity of apply_visitor
by Scott Meyers 25 May '06

25 May '06

If I invoke apply_visitor, what is the time complexity wrt the number of types that may be in the variant? The doc doesn't seem to address this. I looked at the source code, but all I can remember before my head exploded due to exposure to the MPL and the PPL was "switch" (which suggests constant time) and "unrolling" which suggests either linear or constant time, depending on what is being unrolled. Does anybody know what the time complexity of apply_visitor is? My real question is whether applying a visitor to a variant is more efficient than a cascading series of calls to get. I know that the following runs in linear time wrt the number of types in the variant, if (T1 *p = get<T1>(&myVariant)) ... else if (T2 *p = get<T2>(&myVariant)) ... else ... else if (Tn *p = get<Tn>(&myVariant)) ... but what about this? apply_visitor(myVisitor, myVariant); Thanks for any enlightenment. Scott

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Re: [Boost-users] [date_time] Need help with a couple simple problems
by Scott 17 May '06

17 May '06

> #include "boost/date_time/local_time_adjustor.hpp" > #include "boost/date_time/c_local_time_adjustor.hpp" > > ptime local_var > =date_time::c_local_adjustor<ptime>::utc_to_local(utc_var); > > What do you mean by the file is in binary format? Thanks for the help. What I mean is I would like to read/write the value of the ptime in the most efficient way possible. So if the ptime is stored as 2 ints, I would like to (de)serialize 8 bytes (4 bytes each int). Portability isn't an issue. What I would rather *not* do is use something like to_iso_string(ptime) and from_iso_string(ptime). The string representation is rather long. But if that's the only way to do it, guess I'll have to make do. Thanks, Scott

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mpl, apply, placeholders
by Kiuhnm 09 May '06

09 May '06

I am just a beginner so my question could be very stupid. Please be patient. What is wrong with the following code? It should be clear enough what I am trying to do. >>> #include <iostream> #include <boost/mpl/int.hpp> #include <boost/mpl/apply.hpp> #include <boost/mpl/plus.hpp> int main() { using namespace boost::mpl; // ... typedef apply< plus< _, int_<10> >, int_<1> >::type t; std::cout << typeid(t).name() << std::endl; typedef apply< plus< _, int_<10> >, _ > t2; typedef apply< t2, int_<1> >::type res; // ??? std::cout << typeid(res).name() << std::endl; } <<< Kiuhnm -- View this message in context: http://www.nabble.com/mpl%2C-apply%2C-placeholders-t1379886.html#a3705111 Sent from the Boost - Users forum at Nabble.com.

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[multi-array] [C++ ] multi array dimensions
by Karim Bakir 05 May '06

05 May '06

Hi , I want to known if exists method which give us the dimension of a multi array ...I see the documentation and i 'will say no , if no, does it exist a method to determine the dimension of a multi array ? Thanks.

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[Unit-Test] How to test private functions
by Leif Gruenwoldt 05 May '06

05 May '06

Is there a way to test the private functions of a class without moving them into public scope during test? What are some strategies for this? I was hoping to add "friend class boost::unit_test::test_suite;" to my class but that didn't work. -- Leif Gruenwoldt

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[shmem] New bugfix version in Boost Vault and sandbox cvs
by Ion Gaztañaga 04 May '06

04 May '06

Hi to all, I've just uploaded to Boost Vault a new version of Shmem (0.92). You can download it here: http://boost-consulting.com/vault/index.php?direction=&order=&directory=Mem… Online documentation here: http://ice.prohosting.com/newfunk/boost/libs/shmem/ Changes in 0.92: ----------------- * Solved bugs in flat_xxx insert functions. * Solved ambiguous windows native function calls with some header orderings. * Changed named_mutex to support scoped_lock. * Added missing <exceptions.hpp> include in named_mutex. * Added get_instance_type, get_instance_length and get_instance_name functions to front-ends. Warning: -------- Peter Johson has detected a problems with Vc8 and global optimization (/Og). Some tests have shown a possible compiler bug. vc7.1 has no problems with /Og. I'm investigating this but meanwhile I recommend disabling /Og (which is deprecated in vc8) when using Shmem. Special thanks to Peter Johnson, Harold Pirtle and Jan Stetka for their help on this version. Regards, Ion

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Boost lambda: iter_swap and treating lambda as iterator.
by chun ping wang 04 May '06

04 May '06

K the question is simple. How do i do iterator swap with lambda. lets say i have vector of U. vector<U> vecU; typedef vector<U>::iterator iter; iter beg(vecU.begin()); for_each(vec.begin(), vec.end(), ( if_(_1 == *beg) [ // swap the iterator between the current one and begin. ] ) );

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[program_options] Abort trap by store
by Pascal Vizeli 02 May '06

02 May '06

Hi, I habe a problem with store(parse_config_file(...), ...); I don't know why... That isn't my first program with program_options but it is my first program with parse_command_line and parse_config_file in one. Here is my code. First I parse the command line, second I parse the config file. Is it a very simple script. With my debuger (gdb and ddd) I can see, that the problem is here: bpo::store(bpo::parse_config_file(conf_file, desc_file), vm); (at the "end" from script). vm is global definiert. The Namspace bpo ist boost::program_options I use the gcc 3.3.5 and I compile static with: /usr/local/lib/libboost_program_options-gcc-1_33_1.a My OS is OpenBSD What I make false? My script is at the end. Sorry for my bad english. I thanks for Help, Dear, Pascal Vizeli [cpp] bpo::variables_map vm_cmd; bpo::options_description desc_file("config file"), desc_cmd("command line"); // Make options descriptions desc_cmd.add_options() ("config,c", bpo::value<std::string>(), "The Config file") ("help,h", "produce help message") ; desc_file.add_options() ("port", bpo::value<int>()->default_value(6667), "IRC Server Port") ("server", bpo::value<char *>(), "IRC Server IP") ("nick", bpo::value<std::string>(), "Bot Nick") ("user", bpo::value<std::string>(), "username hostname servername :realname") ("nickserv", bpo::value<std::string>(), "Nickserv Identify string") ("oper-pw", bpo::value<std::string>(), "Oper Password") ("mode", bpo::value<std::string>(), "Mode for Bot") ("logchan", bpo::value<std::string>(), "A #Chan for logs") ("logchan_status", bpo::value<int>(), "Logchan On or Off") ("invite-chan", bpo::value<int>(), "Invite for logchan?") ("invite-command", bpo::value<std::string>(), "Invite Command") ("re-chan", bpo::value<int>(), "Refresh Channellist until SEC") ("logfile", bpo::value<std::string>(), "File for logs") ("chroot", bpo::value<char *>(), "Set the chroot dir (path)") ; // Parse CMD bpo::store(bpo::parse_command_line(argc, argv, desc_cmd), vm_cmd); bpo::notify(vm_cmd); if(vm_cmd.count("help")){ std::cout << desc_cmd << std::endl; std::cout << desc_file << std::endl; exit(0); } if(!vm_cmd.count("config")){ printo_err("Config file not found! Use --help for Infos"); exit(0); } // Open Config file std::ifstream conf_file(vm_cmd["config"].as<std::string>().c_str()); if(conf_file.is_open()){ // Parse Config file bpo::store(bpo::parse_config_file(conf_file, desc_file), vm); // Here is the false say my debuger bpo::notify(vm); }else{ printo_err("can't open the conf file!"); exit(0); } [/cpp]

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