Bug 2498 - Can't call Start on Threads without crash
Summary: Can't call Start on Threads without crash
Status: RESOLVED FIXED
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: 5.0
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2011-12-14 10:56 UTC by Clay Fowler
Modified: 2011-12-14 11:19 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Clay Fowler 2011-12-14 10:56:42 UTC
On the beta channel (version info below), any attempt to call Start() on instances of Thread die with a NullReferenceException at this point in Thread.cs:

		IDisposable GetNSAutoreleasePool ()
		{
			if (nsautoreleasepool_ctor == null) {
				Type t = Type.GetType ("MonoTouch.Foundation.NSAutoreleasePool, monotouch, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null");
				nsautoreleasepool_ctor = t.GetConstructor (Type.EmptyTypes);
			}
			return (IDisposable) nsautoreleasepool_ctor.Invoke (null);
		}

The variable t is null, so calling t.GetConstructor blows up. Apparently there is no "MonoTouch.Foundation.NSAutoreleasePool, monotouch, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null" to be found.

So, we cannot start any threads with this version.

Version Info:
============
MonoDevelop 2.9.1
Runtime:
	Mono 2.10.7 (tarball Mon Dec  5 20:41:19 EST 2011)
	GTK 2.24.8
	GTK# (2.12.0.0)
Apple Developer Tools:
	 Xcode 4.2 (828)
	 Build 4D199
Monotouch: 5.1.1
Comment 1 Sebastien Pouliot 2011-12-14 11:19:31 UTC
This is already fixed and will be part of MonoTouch 5.1.2 beta.

There are two workarounds possible. You can either:

1. disable linking in your application (but you'll get larger apps and longer build times); or

2. Add some code in your application that will call NSAutoreleasePool - that way the linker won't elimitate it and the reflection call will work.