c – “不允许不完整类型”错误是什么意思？

我试图在C中声明一个回调例程,如下所示：

void register_rename (int (*function) (const char *current,const char *new));
    /*------------------------------------------------------------*/
    /* WHEN:  The callback is called once each time a file is received and
     *   accepted.   (Renames the temporary file to its permanent name)
     * WHAT:  Renames a file from the given current name to the specified new name.
     */

但是,我收到以下错误：

line 204: error #70: 
      incomplete type is not allowed
void register_rename (int (*function) (const char *current,const char *new));

我不知道如何纠正这个问题.我在同一个头文件中声明了其他类似的回调例程,我没有收到此错误.

请帮忙！