Programming PHP, 3rd Edition

Name

usort

Synopsis

bool usort(array array, callable function)

Sorts an array using a user-defined function. The supplied function is called with two parameters. It should return an integer less than 0 if the first argument is less than the second, 0 if the first and second arguments are equal, and an integer greater than 0 if the first argument is greater than the second. The sort order of two elements that compare equal is undefined. See Chapter 5 for more information on using this function.

Returns true if the function was successful in sorting the array, or false otherwise.