[cairo] AC_TRY_RUN vs crosscompile

Uli Schlachter psychon at znc.in
Sat Apr 15 10:55:09 UTC 2017

On 14.04.2017 20:19, Enrico Weigelt, metux IT consult wrote:
> On 14.04.2017 18:20, Uli Schlachter wrote:
>> Also, this check works around a race condition and debugging
>> race conditions is nasty. 
> What race condition exactly ?

Cairo wants to establish a shared memory segment with the X11 server, so
it creates such a segment and tells the X11 server to attach to it.
Afterwards, nothing else should attach to this segment any more, but
both cairo and X11 still have it mapped in memory. Thus, cairo wants to
get rid of the memory segment (but without unmapping it).

The race condition now is: If cairo deletes the segment before the X11
server attached, the server will fail to attach. If the server is
faster, things will work out.

That's a race.

"Every once in a while, declare peace. It confuses the hell out of your
 - 79th Rule of Acquisition

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