On 05.10.2017 22:31, Steven Watanabe via Boost-build wrote:

AMDG

On 10/05/2017 08:12 PM, Stefan Seefeld via Boost-build wrote:

<snip>
I'm looking at 
https://github.com/boostorg/build/blob/develop/src/engine/make1.c#L326, and 
wonder why, despite the inline comment above the referenced line, this is not 
the first statement to be executed in the make1a function. I understand that the 
make1a function may be called multiple times from different locations, but 
should be ignored (i.e., should be a noop) in all but one case.

However, each time the function is called, its parent's async counter is 
incremented (as long as this target 's progress is not yet RUNNING).

Example:

A depends on C
B depends on C

We enter make1a for C twice, once with each parent,
A and B.  A and B both need to wait for C to complete,
hence we increment the async counter both times.

We only skip this if C has already completed, and
no waiting is required.

Fair enough. However, if the parent counter is incremented, shouldn't there also (directly or indirectly) be a MAKE1B state that is pushed onto the stack for that parent ?
This happens if the child target hasn't started processing, but it doesn't if it's already on the stack.

-- 

      ...ich hab' noch einen Koffer in Berlin...