--- a/src/error.c	Sun Feb 22 07:21:28 2009 +0200
+++ b/src/error.c	Sun Feb 22 07:53:34 2009 +0200
@@ -1,6 +1,12 @@
 
 #include "error.h"
 
+#include <string.h>
+#include <stdio.h>
+
+#include <netdb.h>
+#include <gnutls/gnutls.h>
+
 /*
  * Helper macros
  */
@@ -26,3 +32,39 @@
     }
 }
 
+const char *error_msg (struct error_info *err)
+{
+    static char msg[ERROR_MSG_MAXLEN];
+
+    // intrepret .extra
+    switch (err->code & _ERR_EXTRA_MASK) {
+        case ERR_EXTRA_NONE:
+            // no additional info
+            snprintf(msg, ERROR_MSG_MAXLEN, "%s", error_name(err->code));
+            break;
+        
+        case ERR_EXTRA_ERRNO:
+            // strerror
+            snprintf(msg, ERROR_MSG_MAXLEN, "%s: %s", error_name(err->code), strerror(err->extra));
+            break;
+        
+        case ERR_EXTRA_GAI:
+            // gai_strerror
+            snprintf(msg, ERROR_MSG_MAXLEN, "%s: %s", error_name(err->code), gai_strerror(err->extra));
+            break;
+        
+        case ERR_EXTRA_GNUTLS:
+            // gnutls_strerror
+            snprintf(msg, ERROR_MSG_MAXLEN, "%s: %s", error_name(err->code), gnutls_strerror(err->extra));
+            break;
+        
+        default:
+            // ???
+            snprintf(msg, ERROR_MSG_MAXLEN, "%s(%#.8x): %#.8x", error_name(err->code), err->code, err->extra);
+            break;
+    }   
+
+    // return static pointer
+    return msg;
+}
+