使用cocoa C桥为命令行工具

I am trying to write a command line tool in C and I would like to use some cocoa functions in my program, but I am finding surprisingly few examples that show me how to bridge between C and objective-c, How do I call a simple cocoa function such as posting a notification or controlling the sound volume? I do not know where to start.I am trying to write a command line tool in C a