fix bugs

python/paddle/v2/master/client.py

@@ -26,17 +26,27 @@ class client(object):
             holder[idx] = c_ptr
         lib.paddle_set_dataset(self.c, holder, len(paths))
 
+    # return format: (record, errno)
+    # errno =  0: ok
+    #       = -1: EOF
+    #       < -1: error
     def next_record(self):
         p = ctypes.c_char_p()
         ret = ctypes.pointer(p)
         size = lib.paddle_next_record(self.c, ret)
-        if size < 0:
+        if size == -1:
             # EOF
-            return None
+            return None, -1
+
+        if size < -1:
+            # Error
+            return None, size
+
         if size == 0:
             # Empty record
-            return ""
+            return "", 0
+
         record = ret.contents.value[:size]
         # Memory created from C should be freed.
         lib.mem_free(ret.contents)
-        return record
+        return record, 0

python/paddle/v2/reader/creator.py

@@ -97,7 +97,7 @@ def recordio(paths, addr="", buf_size=100):
         c.set_dataset(paths)
 
         while True:
-            r = client.next_record()
+            r, err = client.next_record()
             if r is None:
                 break
             yield r