Admit that we'll never add the args for a "call" event to the profile

and trace functions; this now declares that None will be passed for the
"call" event.
This closes SF bug/suggestion #460315.

Doc/lib/libpdb.tex

@@ -355,24 +355,25 @@ The events have the following meaning:
 
 \item[\code{'call'}]
 A function is called (or some other code block entered).  The global
-trace function is called; arg is the argument list to the function;
+trace function is called; \var{arg} is \code{None};
 the return value specifies the local trace function.
 
 \item[\code{'line'}]
 The interpreter is about to execute a new line of code (sometimes
 multiple line events on one line exist).  The local trace function is
-called; arg in None; the return value specifies the new local trace
-function.
+called; \var{arg} is \code{None}; the return value specifies the new
+local trace function.
 
 \item[\code{'return'}]
 A function (or other code block) is about to return.  The local trace
-function is called; arg is the value that will be returned.  The trace
-function's return value is ignored.
+function is called; \var{arg} is the value that will be returned.  The
+trace function's return value is ignored.
 
 \item[\code{'exception'}]
-An exception has occurred.  The local trace function is called; arg is
-a triple (exception, value, traceback); the return value specifies the
-new local trace function
+An exception has occurred.  The local trace function is called;
+\var{arg} is a triple \code{(\var{exception}, \var{value},
+\var{traceback})}; the return value specifies the new local trace
+function.
 
 \end{description}
 

Python/ceval.c

@@ -2,7 +2,6 @@
 /* Execute compiled code */
 
 /* XXX TO DO:
-   XXX how to pass arguments to profile and trace functions?
    XXX speed up searching for keywords by using a dictionary
    XXX document it!
    */
@@ -605,7 +604,6 @@ eval_frame(PyFrameObject *f)
 			   whenever an exception is detected. */
 			if (call_trace(tstate->c_tracefunc, tstate->c_traceobj,
 				       f, PyTrace_CALL, Py_None)) {
-				/* XXX Need way to compute arguments?? */
 				/* Trace function raised an error */
 				return NULL;
 			}
@@ -616,7 +614,6 @@ eval_frame(PyFrameObject *f)
 			if (call_trace(tstate->c_profilefunc,
 				       tstate->c_profileobj,
 				       f, PyTrace_CALL, Py_None)) {
-				/* XXX Need way to compute arguments?? */
 				/* Profile function raised an error */
 				return NULL;
 			}