Sun has modified the standard gcc to provide better support for Sun's thread. They used it to build OpenSolaris and it is available under the standard GPL license, ie, it is free. I could build R-2.2.1 with the standard gcc, but I needed to use the gcc from Sun to build 2.3.x. I am not entirely happy with R-2.3.0 because some of the demo(graphics) had their titles clipped, but I want to see how it works in practice. It did pass make check, but I didn't invoke the more strenuous dev checks. /greg