main_user_openflow.c: In function ‘build_multipart_reply’:
main_user_openflow.c:54:57: warning: implicit declaration of function ‘build_opfmsg_reply_ofpbuf’ [-Wimplicit-function-declaration]
         struct ofp_buffer *reply = (struct ofp_buffer *)build_opfmsg_reply_ofpbuf(
                                                         ^
main_user_openflow.c: At top level:
main_user_openflow.c:98:5: error: conflicting types for ‘build_opfmsg_reply_ofpbuf’
 u8 *build_opfmsg_reply_ofpbuf(uint8_t type,uint32_t xid,uint16_t len)
     ^
main_user_openflow.c:54:57: note: previous implicit declaration of ‘build_opfmsg_reply_ofpbuf’ was here
         struct ofp_buffer *reply = (struct ofp_buffer *)build_opfmsg_reply_ofpbuf(
                                                         ^
main_user_openflow.c: In function ‘handle_opfmsg_hello’:
main_user_openflow.c:127:13: warning: implicit declaration of function ‘pkt_print’ [-Wimplicit-function-declaration]
             pkt_print((u8 *)ofpbuf,htons(ofpbuf->header.length));
             ^
main_user_openflow.c: In function ‘main’:
main_user_openflow.c:472:26: warning: passing argument 2 of ‘openflow_hook_init’ from incompatible pointer type [-Wincompatible-pointer-types]
  openflow_hook_init(mask,handle_openflow_callback);
                          ^
In file included from /usr/local/include/fast.h:87:0,
                 from main_user_openflow.c:26:
/usr/local/include/fast_sys_dev.h:69:5: note: expected ‘openflow_msg_callback {aka int (*)(struct ofp_buffer *, int)}’ but argument is of type ‘enum ofperr (*)(struct ofp_buffer *, int)’
 int openflow_hook_init(int mask,openflow_msg_callback callback);
     ^