Added method to check if a socket handle is valid for select()ing it.

git-svn-id: http://yate.null.ro/svn/yate/trunk@2057 acf43c95-373e-0410-b603-e72c3f656dc1

engine/Socket.cpp

@@ -1004,15 +1004,30 @@ int Socket::readData(void* buffer, int length)
 #endif
 }
 
+bool Socket::canSelect(SOCKET handle)
+{
+    if (handle == invalidHandle())
+	return false;
+#ifdef FD_SETSIZE
+#ifndef _WINDOWS
+    if (handle >= FD_SETSIZE)
+	return false;
+#endif
+#endif
+    return true;
+}
+
 bool Socket::select(bool* readok, bool* writeok, bool* except, struct timeval* timeout)
 {
+    if (!valid())
+	return false;
 #ifdef FD_SETSIZE
 #ifndef _WINDOWS
     static bool localFail = true;
     if (m_handle >= FD_SETSIZE) {
 	if (localFail) {
 	    localFail = false;
-	    Debug(DebugFail,"Socket::select: handle %d larger than compiled in maximum %d",
+	    Debug(DebugGoOn,"Socket::select: handle %d larger than compiled in maximum %d",
 		m_handle,FD_SETSIZE);
 	}
 	return false;

yateclass.h

@@ -4411,6 +4411,20 @@ public:
      */
     SOCKET acceptHandle(struct sockaddr* addr = 0, socklen_t* addrlen = 0);
 
+    /**
+     * Check if a socket handle can be used in select
+     * @param handle The socket handle to check
+     * @return True if the socket handle can be safely used in select
+     */
+    static bool canSelect(SOCKET handle);
+
+    /**
+     * Check if this socket object can be used in a select
+     * @return True if this socket can be safely used in select
+     */
+    inline bool canSelect() const
+	{ return canSelect(handle()); }
+
     /**
      * Create a new socket by peeling off an association from a SCTP socket
      * @param assoc Identifier of the association to peel off