Find minimum difference between numbers in array STDIN: Array of integers

STDOUT: Smallest difference (the difference between the closest two numbers in the array).

Rules: Given an array of positive integers find the difference between the closest two numbers in the array. Performance should be taken into consideration.

Example:

STDIN: [55, 99, 6, 29, 1, 523, 3]

STDOUT: 2 (e.g. 3-1)

Scoring: Although somewhat informal, the shortest, most efficient (performance wise) will win. Creativity will also be taken into consideration.
The R language

23 characters,  O(n log n)

min(diff(sort(scan())))


Example:

&gt; min(diff(sort(scan())))
1: 55 99 6
4: 29 1 523 3
8: 
Read 7 items
[1] 2


...The [1] 2 shows the result 2. (the [1] is to keep track of where in the result vector your are since in R all values are vectors - in this case of length 1)