When perl is compiled with -DDEBUGGING, this prints to STDERR the information given by the arguments, prefaced by the name of the file containing the script causing the call, and the line number within that file.

If the v (verbose) debugging option is in effect, the process id is also printed.

The two forms differ only in that deb_nocontext does not take a thread context (aTHX) parameter, so is used in situations where the caller doesn't already have the thread context.

This is like "deb", but args are an encapsulated argument list.

Dump the current stack