Re: AC_TRY_RUN vs crosscompile
Uli Schlachter <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <[email protected]> |
Hi, On 12.04.2017 18:03, Enrico Weigelt, metux IT consult wrote: > just seen that we've got an AC_TRY_RUN call, which - obviously - can't > work when crosscompiling. (it just wildly guesses in that case). Yes, it guesses. However, in this case "no" is always a safe guess (see below). > It's in the CAIRO_ENABLE_SURFACE_BACKEND(xlib...) block. > > What's the actual goal of that ? The code says/does: AC_DEFINE(IPC_RMID_DEFERRED_RELEASE, 1, [Define to 1 if shared memory segments are released deferred.]) So this test some runtime behaviour of the OS (does shmat() after shmctl(IPC_RMID) still work?). Looking at the C code, there is just one "#ifdef IPC_RMID_DEFERRED_RELEASE" and that just does an XSync() if that feature is not there, so this is just a minor performance optimisation. Always doing that XSync() causes no problems. > It also checks for sysv-ipc headers ... is there any chance that some > system could have xlib and xext, but no sysv-ipc headers at all ? I bet that someone somewhere has such a system. How well cairo works there is another question... Cheers, Uli -- Bitte nicht mit dem verbleibenden Auge in den Laser gucken. - Vincent Ebert -- cairo mailing list [email protected] https://lists.cairographics.org/mailman/listinfo/cairo