function::thread_indent_depth — returns the nested-depth of the current task
thread_indent_depth:long(delta:long)
This function returns an integer equal to the nested
function-call depth starting from the outermost initial level. This function
is useful for saving space (consumed by whitespace) in traces with long
nested function calls. Use this function in a similar fashion to
thread_indent
, i.e., in call-probe, use thread_indent_depth(1) and in
return-probe, use thread_indent_depth(-1)