ios - How to use a chained blocks

Question

I'm a newbie with code blocks. I came across this method declaration in Imgur API.

+ (void)uploadImageWithFileURL:(NSURL *)fileURL success:(void (^)(IMGImage *image))success progress:(NSProgress * __autoreleasing *)progress  failure:(void (^)(NSError * error))failure;

Whats the right way of using this sort of methods? It gives me a compiler error when I try to use it as a chained blocks.

This is how I tried

[IMGImageRequest uploadImageWithFileURL:[NSURL URLWithString:@"/temp.jpg"] success:^(IMGImage *image) {

    } progress:(NSProgress *__autoreleasing *){

    }failure:^(NSError *error) {

    }];

Thanks in advance.

Answer 1

The ^ means pass a block of code with parameters as described, the double * on the NSProgress object means you allocate an object (pointer), then pass a pointer to that pointer...

NSURL *fileURL = // create a URL
NSProgress *progress;

[SomeClass uploadImageWithFileURL:fileURL success:^(IMGImage *image) {
    // success code goes here
} progress:&progress  failure:^(NSError * error) {
    // error code goes here
}];

SomeClass is the class that provides this (class) method.