Macro for safely call nil block

test.m

// gcc test.m -o test -framework Foundation
#import <Foundation/Foundation.h>

#define safeblock(block) ((typeof(block))(block ? ((id)block) : ((id)^{})))

int main() {
	void (^block)(NSString *) = ^(NSString *anArgument){
		NSLog(@"Hello %@", anArgument);
	};
	safeblock(block)(@"world");
	block = nil;
	safeblock(block)(@"world");
}