Description

_traceback is an intrinsic integer variable whose value controls whether or not a traceback of the call stack is to be generated upon error. If _traceback is greater than zero, a full traceback will be generated, which includes the values of local variables. If the value is less than zero, a traceback will be generated without local variable information, and if _traceback is zero the traceback will not be generated.

Local variables are represented in the form $n where n is an integer numbered from zero. More explicitly, $0 represents the first local variable, $1 represents the second, and so on. Please note that function parameters are local variables and that the first parameter corresponds to $0.