- Update a few places to account for va_copy().

- Create a separate 'return values' section and move some statements about
  return values to that section.
- Note that each invocation of va_start() and va_copy() must be paired with
  va_end() in the same function.

MFC after:	1 week

share/man/man3/stdarg.3

@@ -59,7 +59,7 @@ The include file
 .In stdarg.h
 declares a type
 .Pq Em va_list
-and defines three macros for stepping
+and defines four macros for stepping
 through a list of arguments whose number and types are not known to
 the called function.
 .Pp
@@ -77,7 +77,8 @@ The
 macro initializes
 .Fa ap
 for subsequent use by
-.Fn va_arg
+.Fn va_arg ,
+.Fn va_copy ,
 and
 .Fn va_end ,
 and must be called first.
@@ -93,10 +94,6 @@ macro, it should not be declared as a register variable, or as a
 function or an array type.
 .Pp
 The
-.Fn va_start
-macro returns no value.
-.Pp
-The
 .Fn va_arg
 macro expands to an expression that has the type and value of the next
 argument in the call.
@@ -105,7 +102,9 @@ The parameter
 is the
 .Em va_list Fa ap
 initialized by
-.Fn va_start .
+.Fn va_start
+or
+.Fn va_copy .
 Each call to
 .Fn va_arg
 modifies
@@ -152,18 +151,28 @@ the same number of times as called with
 .Fa src .
 .Pp
 The
+.Fn va_end
+macro cleans up any state associated with the variable argument list
+.Fa ap .
+.Pp
+Each invocation of
+.Fn va_start
+or
 .Fn va_copy
-macro returns no value.
+must be paired with a corresponding invocation of
+.Fn va_end
+in the same function.
+.Sh RETURN VALUES
+The
+.Fn va_arg
+macro returns the value of the next argument.
 .Pp
 The
+.Fn va_start ,
+.Fn va_copy ,
+and
 .Fn va_end
-macro handles a normal return from the function whose variable argument
-list was initialized by
-.Fn va_start .
-.Pp
-The
-.Fn va_end
-macro returns no value.
+macros return no value.
 .Sh EXAMPLES
 The function
 .Em foo