Provided by: systemtap-doc_2.3-1ubuntu1_all
function::ustack - Return address at given depth of user stack backtrace
n number of levels to descend in the stack.
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.