In a personal project, I have been using some of the niftier and simpler C99 features like //-style comments, mixed variable declarations and statements, the bool type with its true and false pre-defined values and the uint16_t, int32_t, etc. integral types from stdint.h. They resolve some of the minor irritants I used to face when I am forced to code in C89. I plan to use these features from C99 in all my personal projects written in C. Unfortunately, compiler vendors do not seem too eager to support all the features in C99 even after a better part of a decade after the standard was released! Microsoft is surely not in a hurry to support C99 and GCC and glibc are still not completely there yet. A sad state of affairs. Either the standards committee was eager to get new features into C without a buy-in from the compiler vendors or the C coders have been a little underwhelmed with these features and hence have not been pushing for support for them in their compilers.