PECL Hello World Example?

Hi, I would really want to write the HBCI Pecl extension for Online banking. But I find it a bit difficult to understand all the macros and structures that are being used in the current Packages. Is there a Hello World example on how to make PECL extensions? If there is none, would you know of a better package to learn how to make a wrapper extension for a c library than freeimage, one that builds a class at least? Any help would be very nice. Sebastian Ossio