Added a tcp-connect-nonblocking-example.ss to demonstrate how to

handle nonblocking sockets by continuous polling.

lab/tcp-connect-nonblocking-example.ss

@@ -0,0 +1,32 @@
+#!/usr/bin/env scheme-script
+
+(import (ikarus))
+
+;;; very simple demo for how to connect to a server, 
+;;; send a request and receive a response.
+
+;;; Here, we use an asynchronous IO socket.  We wrap the whole
+;;; operation with an exception handler to handle the would-block
+;;; conditions.  If we do get a would-block condition, we just
+;;; return, causing the read/write operation to be restarted until
+;;; it succeeds.  Pretty lame at this point, but it works.
+
+(define (http-cat host)
+  (with-exception-handler
+    (lambda (c)
+      ;;; just return and let it retry until it succeeds
+      (unless (i/o-would-block-condition? c)
+        (raise c)))
+    (lambda ()
+      (let-values ([(op ip) (tcp-connect-nonblocking host "http")])
+        (let ([op (transcoded-port op (native-transcoder))]
+              [ip (transcoded-port ip (native-transcoder))])
+          (display "GET /\n" op)
+          (display (get-string-all ip))
+          (close-input-port ip)
+          (close-output-port op))))))
+
+(http-cat "www.google.com")
+(newline)
+;(http-cat "127.0.0.1")
+

scheme/last-revision

@@ -1 +1 @@
-1293
+1294

scheme/makefile.ss

@@ -1380,7 +1380,7 @@
     [tcp-connect-nonblocking          i]
     [&i/o-would-block                 i]
     [make-i/o-would-block-condition   i]
-    [i/o-would-block-condition        i]
+    [i/o-would-block-condition?       i]
     [i/o-would-block-port             i]
   ))