CODEWITHSUNDEEP
c++
kelorek
kelorek

Reputation: 6214

c++ compile error building arduino project: variable not declared in this scope

I'm trying to build someone else's c++ project-- I'm using the code from here. It's a release of the project, so I believe it's supposed to work as is. However, on compiling I get this error. I've tried moving __gammaTable into the gamma() function, but am not really sure why this isn't considered in its scope.

src/gamma.cpp:15:9: error: 'prog_uchar' does not name a type
 PROGMEM prog_uchar __gammaTable[]  = {
         ^
In file included from /usr/share/arduino/hardware/arduino/cores/arduino/Arduino.h:8:0,
                 from src/gamma.h:4,
                 from src/gamma.cpp:13:
src/gamma.cpp: In function 'byte gamma(byte)':
src/gamma.cpp:42:27: error: '__gammaTable' was not declared in this scope
     return pgm_read_byte(&__gammaTable[x*2 + 2]);
                           ^
.build/lilypad328/Makefile:339: recipe for target '.build/lilypad328/src/gamma.o' failed
make: *** [.build/lilypad328/src/gamma.o] Error 1
Make failed with code 2

And here's code tripping the error:

#include "gamma.h"

PROGMEM prog_uchar __gammaTable[]  = {
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  1,  1,  1,
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,
    2,  2,  2,  2,  2,  3,  3,  3,  3,  3,  3,  3,  3,  4,  4,  4,
    4,  4,  4,  4,  5,  5,  5,  5,  5,  6,  6,  6,  6,  6,  7,  7,
    7,  7,  7,  8,  8,  8,  8,  9,  9,  9,  9, 10, 10, 10, 10, 11,
   11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 16, 16,
   16, 17, 17, 17, 18, 18, 18, 19, 19, 20, 20, 21, 21, 21, 22, 22,
   23, 23, 24, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30,
   30, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36, 37, 37, 38, 38, 39,
   40, 40, 41, 41, 42, 43, 43, 44, 45, 45, 46, 47, 47, 48, 49, 50,
   50, 51, 52, 52, 53, 54, 55, 55, 56, 57, 58, 58, 59, 60, 61, 62,
   62, 63, 64, 65, 66, 67, 67, 68, 69, 70, 71, 72, 73, 74, 74, 75,
   76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,
   92, 93, 94, 95, 96, 97, 98, 99,100,101,102,104,105,106,107,108,
  109,110,111,113,114,115,116,117,118,120,121,122,123,125,126,127
};

byte gamma(byte x) {
    return pgm_read_byte(&__gammaTable[x*2 + 2]);
}

Upvotes: 1

Views: 4937

Answers (2)

Abednego
Abednego

Reputation: 452

A quick fix is to change "prog_uchar" to "uchar". It looks like the table contains integers in the range (0,255), and "prog_uchar" is supposed to mean "uchar".

But the proper way to fix it is to find where "prog_uchar" is defined, and #include that file.

Upvotes: 1

Martin J.
Martin J.

Reputation: 5118

Your actual error is this:

src/gamma.cpp:15:9: error: 'prog_uchar' does not name a type

You are probably missing the header file where prog_uchar is included:

#include <avr/pgmspace.h>

This error:

src/gamma.cpp:42:27: error: '__gammaTable' was not declared in this scope return pgm_read_byte(&__gammaTable[x*2 + 2]);

simply comes from the fact that, since prog_uchar is missing, the variable __gammaTable is not properly declared.

Upvotes: 1

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