Re: [Boost-build] Summer of Code 2006

From: Zbynek Winkler (zw-bjam_at_[hidden])
Date: 2006-04-24 06:23:11

David Abrahams wrote:

>[Moving to the Boost.Build list; that's where this belongs]
>
>Walter Landry <wlandry_at_[hidden]> writes:
>
>  
>
>>David Abrahams <dave_at_[hidden]> wrote:
>>    
>>
>>>Walter Landry <wlandry_at_[hidden]> writes:
>>>
>>>      
>>>
>>>>[1] For example, I can not figure out how to get it to use g++-4.1
>>>>    instead of the default g++ (which is 4.0).  This is really
>>>>    unacceptable.  It shouldn't take me more than 30 seconds to figure
>>>>    that out.
>>>>        
>>>>
>>>Boost.Build v2:
>>>
>>>        # ~/user-config.jam
>>>        using gcc : : path/to/g++-4.1 ;
>>>
>>>makes g++-4.1 your default gcc.  Of course you can also register your
>>>versions separately:
>>>
>>>        using gcc : 4.0 : g++ ;
>>>        using gcc : 4.1 : path/to/g++-4.1 ;
>>>
>>>couldn't be much easier.
>>>      
>>>
>>This does not do what I want.  I want to be able to type a short
>>command (like "make" or "bjam"), and have it build with the compiler I
>>specified when I configured.  
>>    
>>
>
>It absolutely does do that.
>
>  
>
>>So different directories would use different compilers.  I configure
>>once (with all sorts of esoteric commands and locations), but build
>>many times.
>>    
>>
>
>Oh, you want per-directory sticky selection of default toolset.
>That's an interesting idea, and probably easy to add.
>
>  
>
>>It also does not help that this is not at all like the instructions
>>given on the webpage.  The webpage says that I can run configure in
>>libs/config and copy user.hpp to the right place.  
>>    
>>
>
>Wow, you're pretty confused I think.  "The webpage" you're looking at
>has nothing to do with Boost.Build.  John created a configure script
>to help with the deduction of #defines for the Boost.Config library.
>That's all it does, and that's all it's supposed to do.  This whole
>thing predates Boost.Build by some considerable time (years, I think).
>
>Whatever it is that caused you to be confused about that should be
>fixed in the documentation.  Maybe you can make some useful
>suggestions; I think I'm too close to it.
>
>On the other hand, you can get a working *nix configure/make/make
>install script for all of boost at
>http://www.boost-consulting.com/boost/configure.  It will go out at
>the top level of the next release.
>
>  
>
>>That does not work.
>>    
>>
>
>What, specifically, do you mean when you say that?
>
>  
>
>>It is made even more difficult to debug because bjam prints out
>>unhelpful lines like
>>
>>  gcc-C++-action bin/boost/libs/regex/build/libboost_regex.so/gcc/release/shared-linkable-true/threading-multi/cregex.o
>>
>>instead of the actual command that it is executing.  "bjam --help"
>>gives no clue about how to get the actual command.
>>    
>>
>
>Works for me (using BBv2, v1 is about to be retired):
>
>  %bjam --help
>  Configuration help:
>
>    Configuration file at /usr/home/dave/user-config.jam
>
>   This file is used to configure your Boost.Build installation. Please read
>   the user manual to find out where to put it.
>
>  Available Help:
>
>    These are the available options for obtaining documentation. Some options
>    have additional instructions on how to get more detailed information.
>    Multiple options are allowed and sometimes required. For example, the options
>    that configure the help system still require a regular help request option
>    for any output to be generated.
>
>  * --help; This help message.
>  * --help-usage; How to invoke 'bjam.'
>  * --help-all; Brief information on available modules.
>  * --help <module-name>; Get information about a module.
>  * --help-options; Options for controlling the help display.
>  * --help-output <type>; The type of output to genetare. 'console is formated
>    text echoed to the console (the default);' 'text is formated text appended to
>    the output file;' 'html is HTML output to the file.'
>  * --help-output-file <file>; The file to output the documentation.
>
>  ...found 1 target...
>  %bjam --help-usage
>  Boost.Jam Usage:
>
>    bjam [ options... ] targets...
>
>  * -a; Build all targets, even if they are current.
>  * -fx; Read 'x' as the Jamfile for building instead of searching for the
>    Boost.Build system.
>  * -jx; Run up to 'x' commands concurrently.
>  * -n; Do not execute build commands. Instead print out the commands as they
>    would be executed if building.
>  * -ox; Write the build commands to the file 'x'.
>  * -q; Quit as soon as the build of a target fails. Specifying this prevents
>    the attempt of building as many targets as possible regardless of failures.
>  * -sx=y; Sets a Jam variable 'x' to the value 'y', overriding any value that
>    variable would have from the environment.
>  * -tx; Rebuild the target 'x', even if it is up-to-date.
>  * -v; Display the version of bjam.
>  * --x; Option 'x' is ignored but considered and option. The option is then
>    available from the 'ARGV' variable.
>  * -dn; Enables output of diagnostic messages. The debug level 'n' and all
>    below it are enabled by this option.
>  * -d+n; Enables output of diagnostic messages. Only the output for debug
>    level 'n' is enabled.
>
>  Debug Levels:
>
>    Each debug level shows a different set of information. Usually with the
>    higher levels producing more verbose information. The following levels are
>    supported:
>
>  * 0; Turn off all diagnostic output. Only errors are reported.
>  * 1; Show the actions taken for building targets, as they are executed.
>  * 2; Show quiet actions and display all action text, as they are executed.
>  * 3; Show dependency analysis, and target/source timestamps/paths.
>  * 4; Show arguments of shell invocations.
>  * 5; Show rule invocations and variable expansions.
>  * 6; Show directory/header file/archive scans, and attempts at binding to
>    targets.
>  * 7; Show variable settings.
>  * 8; Show variable fetches, variable expansions, and evaluation of 'if'
>    expressions.
>  * 9; Show variable manipulation, scanner tokens, and memory usage.
>  * 10; Show execution times for rules.
>  * 11; Show parsing progress of Jamfiles.
>  * 12; Show graph for target dependencies.
>  * 13; Show changes in target status (fate).
>
>That's -d+5.
>
>It seems as though it's very difficult to satisfy anybody w.r.t. the
>output of a Build/Install system.  Several people just wanted a
>progress indicator that was otherwise silent, and for a while I was
>convinced that would be best, but was about to change the default and
>many experienced Boost.Build users got very upset about it.  Many
>others didn't like the idea of showing the full text of the build
>actions by default.  Apparently the current output is perfect for many
>people.
>  
>
Have you noticed how long your message is? I use bb2 for some time and I 
already *know* that I should be looking for some "-d" option, however 
going through all the hops to find it in the help would take me some 
time too... How can someone new know that 
"help->invocation->diagnostic->Show rule invocations and variable 
expansions" it the expected way to find how to make the commands echo to 
the console?

Zbynek Winkler

-- 
http://zw.matfyz.cz/     http://robotika.cz/
Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic