Hi Patrik,
The problem appears to be that SendTag...()'s thread uses the NSString that
gets passed to it as an argument after it has already been free'd.
1. [Export ("sendTagWithCategory:")]
2. int SendTagWithCategory (string category);
This will generate code similar to this:
int SendTagWithCategory (string category)
{
NSString str = new NSString (category);
int retval = dispatch_to_objective_c (str);
str.Dispose ();
return retval;
}
As you can see in the above pseudo-binding, the NSString gets immediately
disposed after making the call to Objective-C because it doesn't know that
it shouldn't do that (and I think Apple's coding guidelines state that
these sorts of APIs should clone the input parameters if they intend to use
it asynchronously).
To work around this issue, you'll need to change your binding to:
1. [Export ("sendTagWithCategory:")]
2. int SendTagWithCategory (NSString category);
Once you do that, you'll need to keep your copy of the category string
cached somewhere (such as a member variable on whatever class is calling
TSMobileTagging.SendTagWithCategory()) until you know that the thread had
completed (unfortunately there doesn't seem to be a way to do that?). You
might also be able to define some global NSString category string values
that you use instead of passing around .NET strings.
Hope that helps,
Jeff
On Wed, Apr 10, 2013 at 1:16 PM, Patrik Ahlenius <[email protected]> wrote:
> Hi,
>
> I'm trying to bind an Objective-C library but have run into a problem. One
> of the methods in the binding only works in roughly 1 out of 10 calls, and
> for the most time crashes the app with a SIGSEGV. The functions that
> crashes does according to the library docs spawn of a new thread which
> opens a network connection. Can threading be a part of the problem?
>
> The binding itself is is light, and only binds three methods. Attached at
> the bottom are pastebins to the crashlog (as well as my binding, and the
> Obj-C. headers for the functions bound)
>
> Realize that it probably is most likely diffuclt to give any pointers on
> what could be wrong, but figured i give it a shot anyway in case anyone has
> experienced something similair.
>
> Best regards,
> Patrik
>
> Success/Crashlog: http://pastebin.com/SGVFs8XQ
>
> My binding: http://pastebin.com/ArkHvJHE
>
> Obj-C headers (without unbound methods omitted) :
> http://pastebin.com/EVcms9f3
>
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>
>
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