Re: [Boost-build] late binding with tools based on property settings

From: Mark Evans (evans_mark_at_[hidden])
Date: 2006-01-30 18:52:50

Vladimir,

This is going to be a dumb question - reflects me being a jam rookie.

If in my toolset init I have:

  flags hptnsr.link    .NLD     $(condition) : $(.nld) : unchecked ;
  flags hptnsr.link    .LD      $(condition) : $(.ld)  : unchecked ;

where .nld and .ld have been set to version specific filepaths, and I have the following (naive) rule/action:

rule link ( targets * : sources * : properties * )
{
  if <runtime-link>shared in $(properties)
  {
    .TOOL on $(targets) = $(.LD) ;
    .MAIN on $(targets) += $(.LDMAIN) ;
  }
  else
  {
    .TOOL on $(targets) = $(.NLD) ;
    .MAIN on $(targets) += $(.NLDMAIN) ;
  }
}

actions link bind LIBRARIES
{
  $(.TOOL) -L"$(LINKPATH)" -o "$(<)" "$(>)" "$(.MAIN) "$(LIBRARIES)" -l$(FINDLIBS-ST) -l$(FINDLIBS-SA) $(OPTIONS) 
}

In the rule block, the values of $(.LD), $(.NLD), etc. are nil but not in the action block apparently.  Why is this the case?  Is there a way for the rule block to lay hands on the values?

I can rely on using module-global variable for this stuff as you suggest but then that limits me to supporting only one version of the toolset at any given time.

Thanks, anyone, for help with this conundrum.

Cheers,
Mark

Vladimir Prus <ghost_at_[hidden]> wrote: On Thursday 26 January 2006 15:36, Mark Evans wrote:
> First of all, I'd like to extend my gratitude and  admiration to the
> creators of this cool toolset.  I'm sold on the  concept.
>
>   Now as I said in an earlier email I'm in the process of defining a new 
> toolset for HP NonStop (think Tandem) compilers.  I'm wresting  with the
> following problem:
>
>   The choice of linker tool (ld, nld, eld) for a given program or library 
> depends on target architecture variant and an attribute (pic=yes|no)  that
> can vary within the source tree.  My toolset "nsk" init rule,  thus, cannot
> fix the linker program for the entire source tree.  I  can employ a perl
> script that looks through the flags and then invokes  the appropriate
> linker.  But how would you experts tackle this  problem with bjam rules? 
> Is there an example in the tools  directory or elsewhere that illustrates a
> good pattern for this?

I'd take the simple approach:

rule init
{
 .ld = your-detection-code-for-ld-binary-location ;
    .nld = your-detection-code-for-nld-binary-location ;
}

rule compile ( targets * : sources * : properties * )
{
 if true in $(properties)
 {
  TOOL on $(targets) = $(.nld) ;
 }
 else
 {
  TOOL on $(targets) = $(.ld) ;
 }
}

action compile
{
 $(TOOL) -o $(<) $(>)
}

>   I would search the bjam archives but there doesn't seem to be a search 
> function at the website.  

Hmm, do we indeed have no search on lists.boost.org? Anybody has any ideas if 
this can be added?

- Volodya
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