--- /dev/null
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_ERR_H__
+#define __LWIP_ERR_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef s8_t err_t;
+
+/* Definitions for error constants. */
+
+#define ERR_OK 0 /* No error, everything OK. */
+#define ERR_MEM -1 /* Out of memory error. */
+#define ERR_BUF -2 /* Buffer error. */
+#define ERR_RTE -3 /* Routing problem. */
+
+#define ERR_IS_FATAL(e) ((e) < ERR_RTE)
+
+#define ERR_ABRT -4 /* Connection aborted. */
+#define ERR_RST -5 /* Connection reset. */
+#define ERR_CLSD -6 /* Connection closed. */
+#define ERR_CONN -7 /* Not connected. */
+
+#define ERR_VAL -8 /* Illegal value. */
+
+#define ERR_ARG -9 /* Illegal argument. */
+
+#define ERR_USE -10 /* Address in use. */
+
+#define ERR_IF -11 /* Low-level netif error */
+#define ERR_ISCONN -12 /* Already connected. */
+
+#define ERR_TIMEOUT -13 /* Timeout. */
+
+#define ERR_INPROGRESS -14 /* Operation in progress */
+
+
+#ifdef LWIP_DEBUG
+extern const char *lwip_strerr(err_t err);
+#else
+#define lwip_strerr(x) ""
+#endif /* LWIP_DEBUG */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_ERR_H__ */