Index: src/OFStream.m
==================================================================
--- src/OFStream.m
+++ src/OFStream.m
@@ -1805,11 +1805,11 @@
 	return _blocking;
 }
 
 - (void)setBlocking: (bool)enable
 {
-#if defined(HAVE_FCNTL)
+#if defined(HAVE_FCNTL) && !defined(OF_MORPHOS)
 	bool readImplemented = false, writeImplemented = false;
 
 	@try {
 		int readFlags;
 

Index: src/OFStreamSocket.m
==================================================================
--- src/OFStreamSocket.m
+++ src/OFStreamSocket.m
@@ -122,14 +122,18 @@
 #endif
 
 	return (size_t)bytesWritten;
 }
 
-#ifdef OF_WINDOWS
+#if defined(OF_WINDOWS) || defined(OF_MORPHOS)
 - (void)setBlocking: (bool)enable
 {
+# ifdef OF_WINDOWS
 	u_long v = enable;
+# else
+	char v = enable;
+# endif
 
 	if (ioctlsocket(_socket, FIONBIO, &v) == SOCKET_ERROR)
 		@throw [OFSetOptionFailedException
 		    exceptionWithObject: self
 				  errNo: of_socket_errno()];

Index: src/socket_helpers.h
==================================================================
--- src/socket_helpers.h
+++ src/socket_helpers.h
@@ -46,17 +46,19 @@
 
 #ifndef SOCK_CLOEXEC
 # define SOCK_CLOEXEC 0
 #endif
 
-#if !defined(OF_WINDOWS) && !defined(OF_WII)
-# define closesocket(sock) close(sock)
-#endif
-
-#ifdef OF_MORPHOS
+#if defined(OF_MORPHOS)
+# include <sys/filio.h>
+# define closesocket(sock) CloseSocket(sock)
+# define ioctlsocket(fd, req, arg) IoctlSocket(fd, req, arg)
 # define hstrerror(err) "unknown (no hstrerror)"
+# define SOCKET_ERROR -1
 typedef uint32_t in_addr_t;
+#elif !defined(OF_WINDOWS) && !defined(OF_WII)
+# define closesocket(sock) close(sock)
 #endif
 
 #ifdef OF_MORPHOS_IXEMUL
 typedef uint32_t in_addr_t;
 #endif