"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;

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. — Gerben, Apr 14 '15 at 16:33
Which version of the IDE are you using? I was able to compile to code on 1.0.5 — rslite, Apr 16 '15 at 02:41
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. — NULL, Apr 16 '15 at 11:05

score 0 · Accepted Answer · answered Aug 22 '15 at 01:40

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.

"variable must be const" fix for Arduino progrem

1 Answers1