strange behavior of lua_getfield

I have spotted strange behavior with lua_getfield() function. Please look at this code fragment, which should just get a field from table located at the stack top:

if(lua_istable(L,-1)){
  lua_getfield(L,-1,"field_name");
  int type = lua_type(L,-1);         // returns LUA_TNIL
  int field_value = lua_tointeger(L,-1); // returns 0

  lua_pop(L,1);

  // and now let's try iterating all table's fields:
  lua_pushnil(L);  // first key
  while(lua_next(L, -2) != 0){
    // uses 'key' (at index -2) and 'value' (at index -1)
    CString key = lua_tostring(L,-2);
    int type = lua_type(L,-1);

    if(key == "field_name"){ // 
      int value = lua_tointeger(L,-1); // returns correct value!!!!  (type == LUA_TNUMBER)
      // ????? what the heck ????
    }

    // removes 'value'; keeps 'key' for next iteration
    lua_pop(L, 1);
  }

The question is, why lua_getfield() doesn't work, while lua_next() works perfectly? I have used lua_getfield() tens of times with no problems and now I'm bumping my head into my keyboard...

reagards Ma开发者_JAVA百科rcin

Problem solved. There was a problem with adjusting the number of results returned by previous call to lua_pcall. What confuses me though, is why lua_next worked correctly when lua_getfield() miserabely failed...