add initial libdl

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1052 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/libdl/dlclose.c

@@ -0,0 +1,36 @@
+/*
+ * File      : dlclose.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2010, RT-Thread Development Team
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rt-thread.org/license/LICENSE
+ *
+ * Change Logs:
+ * Date           Author		Notes
+ * 2010-11-17      yi.qiu	first version
+ */
+
+#include <rtthread.h>
+#include <rtm.h>
+
+int rt_dlclose (void *handle)
+{
+	rt_module_t module;
+	
+	RT_ASSERT(handle != RT_NULL);
+	
+	module = (rt_module_t)handle;
+	module->nref--;
+	
+	if(module->nref <= 0)
+	{
+		rt_module_unload(module);
+	}	
+
+	return RT_TRUE;
+}
+
+RTM_EXPORT(rt_dlclose)
+