add initial libdl

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

components/libdl/dlopen.c

@@ -0,0 +1,39 @@
+/*
+ * File      : dlopen.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>
+
+void* rt_dlopen(const char *filename, int flags)
+{
+	rt_module_t module;
+	
+	RT_ASSERT(filename != RT_NULL);
+
+	/* find in module list */
+	module = rt_module_find(filename);
+	
+	if(module)
+	{
+		module->nref++;
+		return (void*)module;
+	}	
+	else
+	{
+		module = rt_module_open(filename);
+	}	
+}
+
+RTM_EXPORT(rt_dlopen)
+