Re: [Boost-build] Generated header files.

Subject: Re: [Boost-build] Generated header files.
From: Mathias Lorente (mathias.lorente_at_[hidden])
Date: 2008-12-04 09:56:25

Vladimir Prus wrote:
> Mathias Lorente wrote:
>
>
>   
>> First the header files are generated, then my library is built.
>> New definition to build my library:
>>
>>     lib my_lib
>>         : [ glob-tree *.cpp : .svn ]
>>         : <implicit-dependency>../utils//gen
>>           <link>static
>>           <define>BUILDING_LIBRARY
>>           <variant>debug:<define>ENABLE_DEBUG_LOG
>>         ;
>>     
>
> 'implicit-dependency' should refer to the header target, not the utility
> that generates it.
>
> - Volodya
In fact my input and generated files are in subdirectories. When I try: 
<implicit-dependency>my_subdir/header.h I got following error messages:

    c:/travail/boost_1_37_0/tools/build/v2/build\virtual-target.jam:1047:
    in virtual-target.register-actual-name from module virtual-target
    error: Duplicate name of actual target: <p.>res\header.h
    error: previous virtual target {
    Jamfile</c:/travail/tests/bjam/lib>%Jamfile</c:/travail/tests/bjam/lib>.generate-header-res/header.h.H
    { gcc%gcc.link-gen.exe.EXE { gcc%gcc.compile.c++-gen.o.OBJ {
    gen.cpp.CPP } } } { res/header.txt. } }
    ...

But, if I reference the generator utility and remove leading './' 
everything goes right!

To sum up:
- I need to launch bjam twice to update the library with following jam 
file (first time generate header file, second time build the library):

    project : requirements <include>res ;
    make ./res/header.h
      : ../utils//gen ./res/header.txt
      : @generate-header
      : <location>.
      ;
    actions generate-header
    {
      echo $(<)
      $(>[1]) $(>[2])
    }
    lib my_lib
      : [ glob-tree *.cpp : .svn ]
      : <implicit-dependency>../utils//gen
        <link>static
        <define>BUILDING_LIBRARY
        <variant>debug:<define>ENABLE_DEBUG_LOG
      ;

- I get the above error with following jamfile (../utils//gen replaced 
by ./res/header.h):

    project : requirements <include>res ;
    make ./res/header.h
      : ../utils//gen ./res/header.txt
      : @generate-header
      : <location>.
      ;
    actions generate-header
    {
      echo $(<)
      $(>[1]) $(>[2])
    }
    lib my_lib
      : [ glob-tree *.cpp : .svn ]
      : <implicit-dependency>./res/header.h
        <link>static
        <define>BUILDING_LIBRARY
        <variant>debug:<define>ENABLE_DEBUG_LOG
      ;

- I get what I want with this one ('./res/header' replaced by 'res/header'):

    project : requirements <include>res ;
    make res/header.h
      : ../utils//gen res/header.txt
      : @generate-header
      : <location>.
      ;
    actions generate-header
    {
      echo $(<)
      $(>[1]) $(>[2])
    }
    lib my_lib
      : [ glob-tree *.cpp : .svn ]
      : <implicit-dependency>../utils//gen
        <link>static
        <define>BUILDING_LIBRARY
        <variant>debug:<define>ENABLE_DEBUG_LOG
      ;

I hope this post will help someone else.

Thanks again Volodya for your great help.
Mathias