static int lua_Locate( lua_State* L )
  {
    long handle = lua_tonumber( L, 1 );
    const char* beacon_rssi_json = lua_tostring( L, 2 );

    vector<RSSI_INFO> rssi_info_vec;

    FingerprintLocationServer* p = (FingerprintLocationServer*)handle;

    ConvertJson2CppRSSI( beacon_rssi_json, rssi_info_vec );

    double x;
    double y;
    float floor;

    p->UpdateBeaconSignalGetResult( rssi_info_vec, x, y, floor );

    lua_pushnumber(L,x);
    lua_pushnumber(L,y);
    lua_pushnumber(L,floor);

    return 3;
  }

  static const struct luaL_Reg myLib[] =  
  { 
    {"lua_Locate", lua_Locate}, 
    {NULL, NULL}    //数组中最后一对必须是{NULL, NULL}，用来表示结束   
  }; 

  int luaopen_mLualib(lua_State *L) 
  { 
    luaL_register(L, "FPCalc", myLib); 
    return 1;    // 把myLib表压入了栈中，所以就需要返回1 
  }

lua entry thread aborted: runtime error: error loading module 'mLualib' from file '/var/wdd/wrs/webroot/intelligent_lua/mLualib.so':
  /var/wdd/wrs/webroot/intelligent_lua/mLualib.so: undefined symbol: _Z13lua_tolstringP9lua_StateiPm
stack traceback:
coroutine 0:
  [C]: in function 'require'
  /var/wdd/wrs/webroot/intelligent_lua/location.lua:18: in function...

no file './mLualib.lua'
  no file '/usr/local/openresty/luajit/share/luajit-2.1.0-beta1/mLualib.lua'
  no file '/usr/local/share/lua/5.1/mLualib.lua'
  no file '/usr/local/share/lua/5.1/mLualib/init.lua'
  no file '/usr/local/openresty/luajit/share/lua/5.1/mLualib.lua'
  no file '/usr/local/openresty/luajit/share/lua/5.1/mLualib/init.lua'
  no file '/usr/local/openresty/lualib/mLualib.so'
  no file './mLualib.so'
  no file '/usr/local/lib/lua/5.1/mLualib.so'
  no file '/usr/local/openresty/luajit/lib/lua/5.1/mLualib.so'
  no file '/usr/local/lib/lua/5.1/loadall.so'
  no file '/var/wdd/wrs/webroot/intelligent_lua/mLualib.so'

local FPCalc = require "mLualib"

local x, y, floor = FPCalc.lua_Locate(c_addr, umm_json)

ngx.log(ngx.ERR, "lua_Locate:end:返回结果:", "x=" .. x, " y=" .. y, " floor=" .. floor)