title: iOS Facebook SDK startWithGraphPath:parameters post to just SOME friends programmatically
body: <p>In Facebook, you can post something and share it with just <em>some</em> friends.
  How can this be done programmatically on iOS using Facebook SDK? </p>
  
  <p>My App has an "Emergency Button" that sends: a) User Location on a Map (picture); b) An emergency text (message); and c) The post is only shared with the friends the user has chosen in the config. section (privacy).</p>
  
  <pre><code>- (void)sendMessage {
   //Just an Example: Send an Emergency Post with: message, picture, just to SOME friends.
   //This action may not need the User to actually press a button.
  
   //Privacy parameter obtained from:
   //https://developers.facebook.com/docs/graph-api/reference/v2.0/post/
  
   NSMutableDictionary *privacy = [[NSMutableDictionary alloc]initWithObjectsAndKeys:
                                   @"100000278095294,100000278095528", @"allow", //Friends Id separeted with commas.
                                   @"", @"deny",
                                   @"CUSTOM", @"value",         //Privacy Custom Value
                                   nil];
  
  NSMutableDictionary* params = [[NSMutableDictionary alloc] init];
  [params setObject:self.emergencyText          forKey:@"message"];
  [params setObject:self.locationMap            forKey:@"picture"];
  [params setObject:privacy                     forKey:@"privacy"];
  
  [FBRequestConnection startWithGraphPath:@"me/feed"
                               parameters:params
                               HTTPMethod:@"POST"
                        completionHandler:^(FBRequestConnection *connection,
                                            id result,
                                            NSError *error) {
                            if (error) {
                                NSLog(@"Error");
                                NSLog(@"Error descriptcion %@",error.description);
                            }else{
                                NSLog(@"Success");
                            }
  }];
  </code></pre>
  
  <p>}</p>
  
  <p>This code in not running. I get an error from Facebook.
  If I comment this line:</p>
  
  <pre><code>// [params setObject:privacy forKey:@"privacy"];
  </code></pre>
  
  <p>Then it runs fine and I see the post in FB, but it is a <em>public</em> post.</p>
  
  <p>I need to post: message, picture, just to <em>some</em> friends.</p>
  
  <p>Any solution using <code>startWithGraphPath</code> or using any other command is welcome!</p>