Re: [boost] Directory structure not quite right yet?

Subject: Re: [boost] Directory structure not quite right yet?
From: Peter Dimov (lists_at_[hidden])
Date: 2015-01-05 08:37:14

Vladimir Prus wrote:
> On 01/03/2015 06:29 PM, Peter Dimov wrote:
> > Vladimir Prus wrote:
> >
> >> The only important aspect though, speaking as release manager, is that 
> >> if we change this now, we'll likely break a huge number of user
> >> build and automation scripts that expect current layout, lots of 
> >> instructions on the web using current layout, and so forth.
> >
> > Not if we symlink boost to include/boost, I think.
>
> Fair enough, though it would seem that having $BOOST_ROOT/include/boost 
> directory and a $BOOST_ROOT/boost symlink, along with pre-existing scripts 
> and instructions and some "new" ones only adds to complexity/confusion, 
> not improves anything...

The symlink will be a transitory measure, to avoid breaking existing user 
scripts. The official <include> location from that point on will be 
"$BOOST_ROOT/include".

> ... - unless you'll use the new layout for some completely different 
> workflow?

The workflow I have in mind is this:

-- Download bpm.zip, extract bpm.exe and bpm.conf to d:\boost-1.60.0
-- Suppose I only need Boost.System:

D:\boost-1.60.0>bpm install system
bpm: installing module 'system'
bpm: installing module 'assert'
bpm: installing module 'config'
bpm: installing module 'core'
bpm: installing module 'predef'
bpm: installing module 'build'
bpm: the following libraries need to be built:
  system
bpm: (use ./b2 to build)
bpm: recreating header links
bpm: recreating index

-- The "recreating header links" step puts the header links into 
C:\boost-1.60.0\include.

D:\boost-1.60.0>b2 toolset=msvc-8.0

Building the Boost C++ Libraries.

Performing configuration checks

    - symlinks supported       : no
    - junctions supported      : yes
    - hardlinks supported      : yes

Component configuration:

    - system                   : building

...found 261 targets...
...updating 18 targets...

[...]

...updated 18 targets...

The Boost C++ Libraries were successfully built!

The following directory should be added to compiler include paths:

    D:\boost-1.60.0\include

The following directory should be added to linker library paths:

    D:\boost-1.60.0\stage\lib

--
So the user adds -I D:\boost-1.60.0\include and -L D:\boost-1.60.0\stage\lib 
to his project and everything is fine thereafter.
I could have symlinked include/boost to boost instead, but it didn't feel 
right. Or, I could have symlinked boost to include/boost, without touching 
Jamroot, but then the headers target sees that boost is a symlink, removes 
it, and proceeds to make its own copies (that's part of its logic - boost is 
a split directory).
So I patched Jamroot and boostcpp.jam instead:
diff --git a/Jamroot b/Jamroot
index 8885fd5..2510dc2 100644
--- a/Jamroot
+++ b/Jamroot
@@ -142,7 +142,7 @@ local all-headers =
for dir in $(all-headers)
{
-    link-directory $(dir)-headers : libs/$(dir)/include/boost : <location>. 
;
+    link-directory $(dir)-headers : libs/$(dir)/include/boost : 
<location>include ;
     explicit $(dir)-headers ;
}
@@ -152,7 +152,7 @@ if $(all-headers)
}
project boost
-    : requirements <include>.
+    : requirements <include>include
       # Disable auto-linking for all targets here, primarily because it 
caused
       # troubles with V2.
       <define>BOOST_ALL_NO_LIB=1
@@ -164,7 +164,7 @@ project boost
       <toolset>como-linux:<define>_GNU_SOURCE=1
       # When building docs within Boost, we want the standard Boost style
       <xsl:param>boost.defaults=Boost
-    : usage-requirements <include>.
+    : usage-requirements <include>include
     : build-dir bin.v2
     ;
@@ -226,7 +226,7 @@ for local l in $(all-libraries)
     }
}
-alias headers : $(all-headers)-headers : : : <include>.  ;
+alias headers : $(all-headers)-headers : : : <include>include  ;
explicit headers ;
# Make project ids of all libraries known.
diff --git a/boostcpp.jam b/boostcpp.jam
index 7d7f941..230f5ad 100644
--- a/boostcpp.jam
+++ b/boostcpp.jam
@@ -500,7 +500,7 @@ rule post-build ( ok ? )
     {
         if $(ok)
         {
-            local include-path = [ path.native $(BOOST_ROOT) ] ;
+            local include-path = [ path.native $(BOOST_ROOT)/include ] ;
             ECHO "
The Boost C++ Libraries were successfully built!
--
There do exist Jamfiles that use <include>../../.. <include>$BOOST_ROOT 
(those two amount to the same thing, but are repeated for some reason), but 
I tried a few at random and they seemed to work with the new location 
without any changes.