(PECL apd >= 0.2) Echo to the debugging socket

(PECL apd 0.2-0.4) Throw an error, a callstack and then exit

(PECL apd >= 0.2) Overrides built-in functions

(PECL apd 0.2-0.4) Returns the current call stack as an array

(PECL apd >= 0.2) Starts the session debugging

(PECL apd >= 0.2) Restarts the interpreter

(PECL apd >= 0.2) Renames orig_name to new_name in the global function table

(PECL apd 0.2-0.4) Return all current regular resources as an array

(PECL apd 0.2-0.4) Changes or sets the current debugging level

(Unknown) Outputs the current function table