NAME

       function::ustack - Return address at given depth of user stack backtrace

SYNOPSIS

           ustack:long(n:long)

ARGUMENTS

       n
           number of levels to descend in the stack.

DESCRIPTION

       Performs a simple (user space) backtrace, and returns the element at the specified
       position. The results of the backtrace itself are cached, so that the backtrace
       computation is performed at most once no matter how many times ustack is called, or in
       what order.