Don't get me wrong I am not complaining about a lack of functionality in sprintf what I am getting at is that I don't know how to find out what the IDE will and will not do.
Well whatever C++ functions and features are not available in the arduino platform is most likely not a restriction from the IDE, but rather with the open source tool chain used, the AVR-gcc implementation of the compiler and library in particular. As I recall from some of the guru software comments on this issue a lot of the 'restrictions' are just from the reality of using a microcontroller that only has 2K or SRAM space (8K for a mega board) in which to operate in. Also the microcontroller being based on the classic Harvard computer architecture is probably another 'restriction'?
Lefty