+ Check arguments of select-ports/port-channels

+ Fix typo in really-select-port-channels

scsh/newports.scm

@@ -949,7 +949,15 @@
 
 		 (values n-read-ready n-write-ready 0)))))))))
 
+(define (verify-select-port-arguments! proc lst)
+  (for-each (lambda (p)
+	      (or (input-port? p)
+		  (output-port? p)
+		  (call-error "Argument not a port" proc p)))
+	    lst))
+
 (define (select-ports timeout . ports)
+  (verify-select-port-arguments! select-ports ports)
   (let ((read-list (filter input-port? ports))
 	(write-list (filter output-port? ports)))
 
@@ -969,6 +977,7 @@
 	  (really-select-port-channels timeout read-list write-list)))))
 
 (define (select-port-channels timeout . ports)
+  (verify-select-port-arguments! select-ports ports)
   (let ((read-list (filter input-port? ports))
 	(write-list (filter output-port? ports)))
 
@@ -1007,5 +1016,6 @@
 	       (filter (lambda (write-port)
 			 (any (lambda (write-channel)
 				(eq? write-channel
-				     (port/fdes->output-channel write-port)))))
+				     (port/fdes->output-channel write-port)))
+			      ready-write-channels))
 		       write-list))))))