Subject: [Boost-commit] svn:boost r79581 - trunk/tools/build/v2/build
From: jurko.gospodnetic_at_[hidden]
Date: 2012-07-18 09:24:40
Author: jurko
Date: 2012-07-18 09:24:40 EDT (Wed, 18 Jul 2012)
New Revision: 79581
URL: http://svn.boost.org/trac/boost/changeset/79581
Log:
Updated Boost Build implementation note comment related to why it adds an INCLUDES relation between all sources registered for a single Boost Build action.
Text files modified:
trunk/tools/build/v2/build/virtual-target.jam | 16 ++++++++++++++--
trunk/tools/build/v2/build/virtual_target.py | 26 ++++++++++++++++++--------
2 files changed, 32 insertions(+), 10 deletions(-)
Modified: trunk/tools/build/v2/build/virtual-target.jam
==============================================================================
--- trunk/tools/build/v2/build/virtual-target.jam (original)
+++ trunk/tools/build/v2/build/virtual-target.jam 2012-07-18 09:24:40 EDT (Wed, 18 Jul 2012)
@@ -761,14 +761,26 @@
DEPENDS $(actual-targets) : $(self.actual-sources)
$(self.dependency-only-sources) ;
- # This works around a bug with -j and actions that produce multiple
- # target, where:
+ # This used to work around a bug with -j and actions that produce
+ # multiple targets, where:
# - dependency on the first output is found, and the action is
# started
# - dependency on the second output is found, and bjam noticed that
# command is already running
# - instead of waiting for the command, dependents of the second
# targets are immediately updated.
+ # Current Boost Jam implementation already works around the problem
+ # the same way internally. The only difference being that it does
+ # so only when an actual Boost Jam action is encountered while we
+ # do this even if our Boost Build action actually modeling a rule
+ # that will then register one or more Boost Jam actions. In that
+ # case our INCLUDES relation added here will affect the build
+ # behaviour but it will not be solving any actual problem. The only
+ # thing it might seem like it is doing is forcing multiple separate
+ # actions to be run all together or none at all but it will not do
+ # that completely either - it would miss the case when one of the
+ # action targets depends on a target that needs to be updated and
+ # another does not.
if $(actual-targets[2])
{
INCLUDES $(actual-targets) : $(actual-targets) ;
Modified: trunk/tools/build/v2/build/virtual_target.py
==============================================================================
--- trunk/tools/build/v2/build/virtual_target.py (original)
+++ trunk/tools/build/v2/build/virtual_target.py 2012-07-18 09:24:40 EDT (Wed, 18 Jul 2012)
@@ -797,14 +797,24 @@
self.engine_.add_dependency (actual_targets, self.actual_sources_ + self.dependency_only_sources_)
- # This works around a bug with -j and actions that
- # produce multiple target, where:
- # - dependency on the first output is found, and
- # the action is started
- # - dependency on the second output is found, and
- # bjam noticed that command is already running
- # - instead of waiting for the command, dependents
- # of the second targets are immediately updated.
+ # This used to work around a bug with -j and actions that produce
+ # multiple targets, where:
+ # - dependency on the first output is found, and the action is started
+ # - dependency on the second output is found, and bjam noticed that
+ # command is already running
+ # - instead of waiting for the command, dependents of the second
+ # targets are immediately updated.
+ # Current Boost Jam implementation already works around the problem the
+ # same way internally. The only difference being that it does so only
+ # when an actual Boost Jam action is encountered while we do this even
+ # if our Boost Build action is actually modeling a rule that will then
+ # register one or more Boost Jam actions. In that case our INCLUDES
+ # relation added here will affect the build behaviour but it will not be
+ # solving any actual problem. The only thing it might seem like it is
+ # doing is forcing multiple separate actions to be run all together or
+ # none at all but it will not do that completely either - it would miss
+ # the case when one of the action targets depends on a target that needs
+ # to be updated and another does not.
if len(actual_targets) > 1:
bjam.call("INCLUDES", actual_targets, actual_targets)