单片机新手求助该警告怎么消除*** WARNING L1:？

WARNING L1: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  _SENDCHAR
    MODULE:  main1051.obj (MAIN1051)
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  INIT
    MODULE:  main1051.obj (MAIN1051)
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  COMBUF
    MODULE:  main1051.obj (MAIN1051)
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  INIT
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0801H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0806H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 080DH
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMBUF
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 081AH
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMBUF
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0821H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0823H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0830H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMBUF
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0834H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  _SENDCHAR
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 083BH
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  COMPOINTER
    MODULE:  main1051.obj (MAIN1051)
    ADDRESS: 0843H