Just like with C, you can declare a function to have a specific return type.
You can specify many return types, including int, long, bool and float.
For debugging purposes, have a look at the Sample Programs\NXT\NXT Feature Samples\Debug Stream.c
program. I use this extensively.
| Professional Conduit of Reasonableness
| (Title bestowed upon on the 8th day of November, 2013)
| My Blog: I'd Rather Be Building Robots
| ROBOTC 3rd Party Driver Suite: [Project Page