diff --git a/src/include/lib3270.h b/src/include/lib3270.h
index 69e9b2e..4114cdc 100644
--- a/src/include/lib3270.h
+++ b/src/include/lib3270.h
@@ -1035,7 +1035,7 @@
 	 * @param c		Pointer to character.
 	 * @param attr	Pointer to attribute.
 	 *
-	 * @return 0 if ok or error code.
+	 * @return 0 if ok, -1 if fails (sets errno).
 	 *
 	 */
 	LIB3270_EXPORT int lib3270_get_element(H3270 *h, int baddr, unsigned char *c, unsigned short *attr);
diff --git a/src/lib3270/private.h b/src/lib3270/private.h
index 44024cf..adc6ac1 100644
--- a/src/lib3270/private.h
+++ b/src/lib3270/private.h
@@ -633,6 +633,11 @@ LIB3270_INTERNAL int	lib3270_default_event_dispatcher(H3270 *hSession, int block
 	LIB3270_INTERNAL void check_session_handle(H3270 **hSession);
 #endif // DEBUG
 
+LIB3270_INTERNAL int check_online_session(H3270 *hSession);
+
+/// @brief Returns -1 if the session is invalid or not online (sets errno).
+#define FAIL_IF_NOT_ONLINE(x) if(check_online_session(x)) return -1;
+
 LIB3270_INTERNAL int	non_blocking(H3270 *session, Boolean on);
 
 #if defined(HAVE_LIBSSL) /*[*/
diff --git a/src/lib3270/screen.c b/src/lib3270/screen.c
index 48da3ca..32ef38f 100644
--- a/src/lib3270/screen.c
+++ b/src/lib3270/screen.c
@@ -98,15 +98,18 @@ static void addch(H3270 *session, int baddr, unsigned char c, unsigned short att
 	session->cbk.update(session,baddr,c,attr,baddr == session->cursor_addr);
 }
 
-LIB3270_EXPORT int lib3270_get_element(H3270 *h, int baddr, unsigned char *c, unsigned short *attr)
+LIB3270_EXPORT int lib3270_get_element(H3270 *hSession, int baddr, unsigned char *c, unsigned short *attr)
 {
-	CHECK_SESSION_HANDLE(h);
+    FAIL_IF_NOT_ONLINE(hSession);
 
-	if(!h->text || baddr < 0 || baddr > (h->rows*h->cols))
-		return EINVAL;
+	if(!hSession->text || baddr < 0 || baddr > (hSession->rows*hSession->cols))
+	{
+		errno = EINVAL;
+		return -1;
+	}
 
-	*c		= h->text[baddr].chr;
-	*attr	= h->text[baddr].attr;
+	*c		= hSession->text[baddr].chr;
+	*attr	= hSession->text[baddr].attr;
 
 	return 0;
 }
@@ -394,7 +397,7 @@ LIB3270_EXPORT int lib3270_get_cursor_address(H3270 *h)
  */
 LIB3270_EXPORT int lib3270_translate_to_address(H3270 *hSession, int row, int col)
 {
-	CHECK_SESSION_HANDLE(hSession);
+    FAIL_IF_NOT_ONLINE(hSession);
 
 	row--;
 	col--;
@@ -423,7 +426,7 @@ LIB3270_EXPORT int lib3270_translate_to_address(H3270 *hSession, int row, int co
  */
 LIB3270_EXPORT int lib3270_set_cursor_address(H3270 *hSession, int baddr)
 {
-    CHECK_SESSION_HANDLE(hSession);
+    FAIL_IF_NOT_ONLINE(hSession);
 
 	trace("%s(%d)",__FUNCTION__,baddr);
 
@@ -877,10 +880,10 @@ LIB3270_ACTION( testpattern )
 
 	static const unsigned char gr[] = { 0, GR_UNDERLINE, GR_BLINK };
 
-	int row		= 0;
+	unsigned int row		= 0;
 	int max;
 	int pos 	= 0;
-	int grpos	= 0;
+	unsigned int grpos	= 0;
 	int f;
 	int fg		= COLOR_BLUE;
 
@@ -933,10 +936,13 @@ LIB3270_EXPORT int lib3270_is_protected(H3270 *h, unsigned int baddr)
 {
 	unsigned char fa;
 
-	CHECK_SESSION_HANDLE(h);
+	FAIL_IF_NOT_ONLINE(h);
 
 	if(baddr > (h->rows * h->cols))
+	{
+		errno = EINVAL;
 		return -1;
+	}
 
 	fa = get_field_attribute(h,baddr);
 
diff --git a/src/lib3270/session.c b/src/lib3270/session.c
index 50cc0b2..ef66cae 100644
--- a/src/lib3270/session.c
+++ b/src/lib3270/session.c
@@ -388,6 +388,25 @@ void check_session_handle(H3270 **hSession)
 #endif // ANDROID
 }
 
+LIB3270_INTERNAL int check_online_session(H3270 *hSession) {
+
+	// Is the session valid?
+	if(!hSession)
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
+	// Is it connected?
+	if((int) hSession->cstate < (int)LIB3270_CONNECTED_INITIAL)
+	{
+		errno = ENOTCONN;
+		return -1;
+	}
+
+	return 0;
+}
+
 LIB3270_EXPORT H3270 * lib3270_get_default_session_handle(void)
 {
 	if(default_session)
--
libgit2 0.21.2