I am an experienced iOS developer amongst other things. I have a good mastery of Objective-C and Apple's frameworks in the language.
But when it comes to the C-based frameworks I often hit a ceiling with my knowledge, and often have to look up idioms and syntax. I learnt C from K&R but it's been a while. I did try learning from it again and it was a blast; but by Chapter 6, I got a feeling that its C is a bit archaic, at least idiom-wise. Also, I want to learn C mostly for the sake of iOS development and so a Mac/iOS focused learning process would be ideal.
What will be a good way to go about doing this?