Please make LED_BUILTIN a macro [imported]

[cmaglie]

This is Issue 758 moved from a Google Code project.
Added by 2011-12-22T05:25:10.000Z by c...@zygomorphic.com.
Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Enhancement, Priority-Medium

Original description

Please change LED_BUILTIN from a typed constant to a macro to better support boards that do not have a built-in LED.

[cmaglie]

Fixed.

[matthijskooijman]

Doesn't this actually apply to all other pin definitions in arduino_pins.h (MISO, MOSI, SDA, A0, A1, etc.) as well? It doesn't matter much now, but it's possible that in the future a board without I²C, SPI or ADC is released. Making these constants macros allows checking for them with #if defined conditionals when this happens.

[Lauszus]

I agree with @matthijskooijman. They should also be macros instead.
For instance in the USB Host library we have this: https://github.com/felis/USB_Host_Shield_2.0/blob/82c52542cc522982b026bf7f6cdd9059e5064d4a/usbhost.h#L45-L53. This could easily be replaced if MOSI, MISO, SCK and SS where macros.

[MarkusLange]

static const uint8_t LED_BUILTIN = 13;

is not declared in the \variants\leonardo\pins_arduino.h for the Leonardo in IDE 1.0.5

[cmaglie]

Changing the const int to #include have a subtle side effect, for example the following code:

https://github.com/adafruit/Adafruit-MAX31855-library/blob/master/Adafruit_MAX31855.h#L26

declare parameters name as "MISO", but since we #define MISO to something else, the code is screwed up, an produce errors like the following:

sketch_ac_ino:44: error: no matching function for call to 'Adafruit_MAX31855::Adafruit_MAX31855(int, int, int)'
C:\Users\JSweda\Documents\Arduino\libraries\Adafruit_MAX31855/Adafruit_MAX31855.h:24: 
   note: candidates are: Adafruit_MAX31855::Adafruit_MAX31855() 
   note: Adafruit_MAX31855::Adafruit_MAX31855(const Adafruit_MAX31855&)

The same doesn't happen with the const int declaration (since the local name "hides" the global one).

Any idea?