Re: [PATCH 5/4] run-command: implement abort_async for pthreads

On Fri, Apr 1, 2011 at 11:41 AM, Erik Faye-Lund [off-list ref] wrote:

On Thu, Mar 31, 2011 at 8:45 PM, Jeff King [off-list ref] wrote:

quoted

We just need to cancel the thread, instead of sending it a
signal as we do for fork()'d async sections.

Signed-off-by: Jeff King <redacted>
---
This could also just be part of the merge resolution, but I thought it
would be easier to see what is going on if I put it here.

 run-command.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/run-command.c b/run-command.c
index e31c073..46ea07d 100644
--- a/run-command.c
+++ b/run-command.c

@@ -607,7 +607,7 @@ void abort_async(struct async *async)

 #ifdef NO_PTHREADS

This context-line doesn't match 3/4... Did you send out the wrong
version of that patch?

quoted

       kill(async->pid, 15);
 #else
-       /* no clue */
+       pthread_cancel(async->tid);

My worry about terminating a thread that's currently holding a mutex
(implicitly through the CRT?) still applies though...

OK, I've read up on thread-cancellation, and this code seems correct.
pthread_cancel doesn't kill the thread right away, it just signals a
cancellation-event, which is checked for at certain
cancellation-points. A lot of the CRT functions are defined as
cancellation points, so it'll be a matter for us Win32-guys to
implement pthread_testcancel() and inject that into the
function-wrappers of the CRT functions that are marked as
cancellation-points.