Deleted questions on Stack Overflow sometimes make for great golf material.
Write a function that takes a nonnegative integer as input, and returns true if all the digits in the base 10 representation of that number are unique. Example:
48778584 -> false 17308459 -> true
Character count includes only the function.
If you choose to answer in C or C++: no macros, no undefined behaviour; implementation-defined behaviour and compiler warnings are fine.