[Boost-build] async rule execution

Subject: [Boost-build] async rule execution
From: Stefan Seefeld (stefan_at_[hidden])
Date: 2017-05-10 15:17:06

Hello,

browsing the bjam sources I ran into

                /* Call the callback, may call back to jam rule land. */
                (*cmdtab[ i ].func)( cmdtab[ i ].closure, rstat, &time_info,
                    cmdtab[ i ].buffer[ OUT ], cmdtab[ i ].buffer[ ERR ],
                    cmdtab[ i ].exit_reason );

(https://github.com/boostorg/build/blob/develop/src/engine/execunix.c#L558-L561)

which suggests it's possible to have a callback call into the b2 layer
(i.e., running some post-processing rule coded in Jam). Is that possible
? The only callback implementation I could find was the `make1c_closure`
which is used to collect status information, but which isn't passed
directly on into Jam, and thus can only be processed synchronously once
the call to `builtin_update_now` has completed.

Am I missing anything ?

Thanks,

        Stefan

-- 
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