Andrew wrote:80 characters wide yes, no line limit though. However a very long function is indicative of code smell and you should investigate it and consider refactoring.
I agree, but I don't think that 25 lines is "very long" by modern standards. Around the 100 line mark is where you should start thinking about refactoring.
However, I would like to stress this is indicative of a smell. Some functions are large because they have an inherently ugly job to do which can't be avoided. Don't split up functions just because they're big, and do put some thought into how you split them up. In particular, avoid the Chinese duck algorithm (the split occurs wherever the cleaver happens to fall).