Question

Is it possible to instantiate a NSValue with a pointer to a C structure without having to create a autorelease pool? For the moment, I do this:

NSValue* val = [NSValue valueWithPointer:(const void*)structure];

but this is release by the autorelease pool. I would like to take control of this and be able to dealloc it when I want. Is this possible? I tried this:

NSValue* value = [[NSValue alloc] initWithBytes:(const void*)structure objCType:@encode(const void*)];
[value release];

but it is crashing for some reason. Any other way to be able to release immediately?
Thanks!

Answer 1

You’re supposed to be passing a pointer to the type that’s given for the objCType: argument. You’re passing a variable of the type. So, for example, if you have a variable int foo that you want to store in an NSValue, you’d write [[NSValue alloc] initWithBytes:&foo objCType:@encode(int)]. So if you want to store a pointer, you need to pass a pointer to that pointer as the bytes. Passing the pointer itself will cause NSValue to try to follow the pointer and then treat the bytes that it’s pointing to as a pointer as well.