"variable must be const" fix for Arduino progrem

Question

I am trying to upload to my nano the code attached. It is giving me an error saying variable must be const about something I am trying to put in progrem. I learned that installing a older version of the compiler worked. However I was wondering is there a way to just edit the code to make it work. I tried putting const before it but it didn't work. It is on line 78 and 79 of the first file.

const extern PGM_P *NApowerCodes[] PROGMEM;

const extern PGM_P *EUpowerCodes[] PROGMEM;

• Gerben: Could you please post the concerning lines of code. You can't expect us to go to a webpage, find and download a zip, open it, just to see the code.
• rslite: Which version of the IDE are you using? I was able to compile to code on 1.0.5
• NULL: I am using the latest version, I believe 1.0.06. I was able to compile it with your version but would like to know how to fix it.

Answer 1

Using the source from this link I got it to compile following these steps.

---

• Before opening the sketch in the Arduino:
  • Rename TVB.pde to TVB.ino
  • Rename WORLDcodes.cpp to WORLDcodes.h

---

• Open the sketch (TVB.ino) in the Arduino IDE

---

• Edit main.h and change:

  // The structure of compressed code entries
  struct IrCode {
   uint8_t timer_val;
   uint8_t numpairs;
   uint8_t bitcompression;
   uint16_t const *times;
   uint8_t const*codes;
  };
  

  to:

  // The structure of compressed code entries
  struct IrCode {
   uint8_t timer_val;
   uint8_t numpairs;
   uint8_t bitcompression;
   uint16_t const *times;
   uint8_t const*codes PROGMEM;
  };
  

  That is, add PROGMEM to the codes line.

---

• Edit TVB.ino and change:

  extern PGM_P *NApowerCodes[] PROGMEM;
  extern PGM_P *EUpowerCodes[] PROGMEM;
  extern uint8_t num_NAcodes, num_EUcodes;
  

  to:

  #include "WORLDcodes.h"
  

  This avoids some linker problems in the original code.

---

• Edit WORLDcodes.h and delete the line:

   #include "main.h"
  

---

• Continue editing WORLDcodes.h and change:

  const struct IrCode *NApowerCodes[] PROGMEM = {
  

  to:

  const struct IrCode * const NApowerCodes[] PROGMEM = {
  

  ---

  And also change:

  const struct IrCode *EUpowerCodes[] PROGMEM = {
  

  to:

  const struct IrCode * const EUpowerCodes[] PROGMEM = {
  

It should now compile OK.