Spin: about pointer and structure

Comments

• ersmith Posts: 6,224

  2016-04-21 15:58

  ToDayWeather is declared as a long, but in InsertDayRec you're trying to copy 5 longs into its space; similarly with Tomorrow. Try changing their definitions to:

      long ToDayWeather[weatherParamCount]
      long Tomorrow[weatherParamCount]
  

  
  Also, in the calls to Print_ptrDayWeather you should use @, like:

      Print_ptrDayWeather(@ToDayWeather)
      Print_ptrDayWeather(@Tomorrow)
  
• laurent974 Posts: 77

  2016-04-21 19:41

  Thank you for your answer, but it still doesn't work.
• ersmith Posts: 6,224

  2016-04-21 20:55

  Ah, you also have to remove the long[] in the longmove command:

     longmove(ptrDayWeather,@We_Tmin,weatherParamCount)
  

  
  The reason is that longmove already is dereferencing the pointer internally, so using long[ptrDayWeather] causes a double indirection and makes the data be written to the wrong place in memory.
  
• laurent974 Posts: 77

  2016-04-22 10:39 edited 2016-04-22 19:15

  oh my god it works. thank you !!
  
  i have tried so many things, i knew i was close, and was becoming upset to turn around the solution. now i climbed one march on spin comprehension.
  
  [Update] since it's a beginner question, i post here the whole code, that may help others beginners.
  
  This project contains 2 objects:
  - the first one the structure and the setter are defined
  - The main one which give an array of 3 days of forecast weather.
  
  Weather.spin

  CON 
    weatherParamCount = 5
  
  VAR
  ' weather structure
    long We_Tmin                  ' temperature Min
    long We_Tmax                  ' temperature Max
    long We_Day                   ' pointer to day
    long We_Condition             ' pointer to condition
    long We_Icon                  ' pointer to Icon
  
  
  PUB InsertDayRec(ptrDayWeather, Tmin, Tmax,ptrDay,ptrCondition,ptrIcon)
      We_Tmin      := Tmin
      We_Tmax      := Tmax
      We_Day       := ptrDay
      We_Condition := ptrCondition
      We_Icon      := ptrIcon
      longmove(ptrDayWeather,@We_Tmin,weatherParamCount)
  

  
  Main.spin

  CON
    _clkmode        = xtal1 + pll16x              'Use crystal * 16
    _xinfreq        = 5_000_000                   '5MHz * 16 = 80 MHz
  
    CR              = 13
  
  OBJ
  
    PC            : "Parallax Serial Terminal Extended"
    We            : "Weather"
  
  VAR
    
    long Forecast[3]    ' 3 days of forecast weather
                        ' it's an array of pointers to days
  
  ' DayWeather ptrs
  ' they store the structure of weather's fields
    long ToDayWeather[We#weatherParamCount]
    long Tomorrow[We#weatherParamCount]
    long ThirdDay[We#weatherParamCount]
    
  PUB Main
  
     PC.Start(115_200)                           ' Start Parallax Serial Terminal
     PC.clear
  
     We.InsertDayRec(@ToDayWeather,12,40,string ("Auj"), string("Conditions bonnes"),string("Wind.gif"))
     We.InsertDayRec(@Tomorrow,5,10,string ("tom"), string("Conditions pluvieuses"),string("Rain.gif"))
     We.InsertDayRec(@ThirdDay,15,20,string ("3eme"), string("Beau Temps"),string("Sunny.gif"))
  
     Forecast[0]:= @ToDayWeather
     Forecast[1]:= @Tomorrow
     Forecast[2]:= @ThirdDay
  
     Print_ptrDayWeather(Forecast[2])
     Print_ptrDayWeather(Forecast[1])
     Print_ptrDayWeather(Forecast[0])
     
  PUB Print_ptrDayWeather (ptrDayWeather)
      PC.str(string(CR,CR))
      PC.str(string("Day: "))
      PC.str( long[ptrDayWeather][2] )
  
      PC.str(string(CR))
      PC.str(string("Tmin: "))
      PC.dec( long[ptrDayWeather][0] )
  
      PC.str(string(CR))
      PC.str(string("TMax: "))
      PC.dec( long[ptrDayWeather][1] )
  
      PC.str(string(CR))
      PC.str(string("Condition: "))
      PC.str( long[ptrDayWeather][3] )
  
      PC.str(string(CR))
      PC.str(string("Icon: "))
      PC.str( long[ptrDayWeather][4] )