> On Feb 5, 2015, at 3:54 PM, Graham Cox <graham....@bigpond.com> wrote: > > This is great. Running from XCode I get 7168, archiving and exporting a final > build of my app, I get 256... bingo! Only the built version was seeing this > crash, another reason I was having a lot of trouble debugging it. > > With 50 tasks, creating 50 NSURLSession, that accounts for 100 file > descriptors. I'm supposing the rest come from other places - in fact each of > my tasks potentially creates 2 NSURLSession, though these second ones are > highly conditional on what the first ones return, and usually are NOT > created, so I doubt that I was immediately creating 200 file handles.
You can use `sudo lsof -p <PID> -a -d 0-99999` to list the file descriptors in a process. (The `-d 0-99999` flag hides open files that don't have file descriptors.) >> If you hit that limit you should see errors from various network API. File a >> bug report if you find some API that causing weird crashes instead of >> failing gracefully or halting with an appropriate error message when you run >> out of file descriptors. > > Well I'm seeing EXC_GUARD. Is that considered "graceful"? From the user's > perspective it isn't, because it causes summary termination of the app which > is almost always reported as "it crashed, wah!, you suck!". Ultimately this > should propagate up to the NSURLSession API in some way - e.g. by returning > nil instead of an object if it can't create its resources. I think one > problem there is that the API is asynchronous - it creates the object which > then starts a thread to open the socket - that's what the stack trace implies > anyway. That would make it hard to simply not return a valid object. Not sure > what the right design would be there - that's one for the networking > architects to ponder I guess. EXC_GUARD is very bad, usually on the order of use-after-free bad. Acceptable results are an error or exception from the API, preferably one that says "too many open files", or a crash log that says "too many open files". Anything that doesn't say "too many open files" somewhere is hard to diagnose. -- Greg Parker gpar...@apple.com Runtime Wrangler _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
