userinfo in NSTimer iOS4

I want to pass some data to the fire method.So I use the 'userInfo'

I did like this:

struct MyStruct* userinfo = malloc(sizeof(struct MyStruct));

userinfo->a = 1;
userinfo->开发者_如何学JAVA;b = 2;

NSTimer *myTimer = [NSTimer scheduledTimerWithInterval:0.05 target:self selector:@selector(myFireMethod:) userInfo:userinfo repeats:YES];

But the problem happened,the iOS app crashed when running the scheduledTimerWithInterval method.

It must be something wrong with 'userinfo' .What's the probably mistake?

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userInfo has to be Objective C object, cause it's retained during assignment.

If you want to pass C-struct you have to wrap it with NSValue:

NSValue* val = [NSValue valueWithPointer: your_struct_ptr];