Copying blocks (ie: copying them to instance variables) in Objective-C
- by RyanWilcox
I'm trying to understand blocks. I get how to use them normally, when passed directly to a method. I'm interested now in taking a block, storing it (say) in an instance variable and calling it later.
The blocks programming guide makes it sound like I can do this, by using Block_copy / retain to copy the block away, but when I try to run it I crash my program.
- (void) setupStoredBlock
{
int salt = 42;
m_storedBlock = ^(int incoming){ return 2 + incoming + salt; };
[m_storedBlock retain];
}
I try to call it later:
- (void) runStoredBlock
{
int outputValue = m_storedBlock(5);
NSLog(@"When we ran our stored blockwe got back: %d", outputValue);
[m_storedBlock release];
}
Anyone have any insights? (Or, is there something I'm not getting with blocks?)
Thank you very much!
