According to the style guide we must declare variables as close as possible to their respective definitions(I think the same is applicable to ```buf_T *buf```). If you did it for optimisation purposes these threads explain why it is not needed: http://stackoverflow.com/questions/8735765/variables-declared-inside-a-loop http://stackoverflow.com/questions/7959573/declaring-variables-inside-loops-good-practice-or-bad-practice-2-parter