"not a constant expression" error about a21

[aleh]

Thanks for reporting this!

Apparently the above happens in newer versions of Arduino IDE because of a change in GCC that does not allow constant expressions to contain pointers constructed from integers, something that port addresses are on AVR, see the discussion here, for example, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49171#c18.

I am trying to work around this annoying rule now by using constexpr functions instead. I'll keep you posted.

[aleh]

@kurogedelic It should be working with the new version as well now, could you please try?

[kurogedelic]

@aleh Thank you.
I tried the new version. With your "NoiseChip.ino." But it can't worked.
It shows different error messages.
The "not a constant expression" error is no longer visibled.

Arduino：1.8.13 (Mac OS X), TD: 1.53, Board: "ATtiny25/45/85, ATtiny85, Internal 1 MHz"

In file included from /Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:12:0,
				 from /Users/<user>/Documents/Arduino/libraries/a21-master/a21.hpp:16,
				 from /Users/<user>/NoiseChip/NoiseChip.ino:18:
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/flashstring.hpp:11:9: error: 'fstr_t' does not name a type; did you mean 'fpos_t'?
 typedef fstr_t *FlashStringPtr;
		 ^~~~~~
		 fpos_t
In file included from /Users/<user>/Documents/Arduino/libraries/a21-master/a21.hpp:16:0,
				 from /Users/<user>/NoiseChip/NoiseChip.ino:18:
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:478:14: error: 'FlashStringPtr' has not been declared
   void print(FlashStringPtr str) {
			  ^~~~~~~~~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:486:8: error: 'void a21::PCD8544Console<lcd, font>::print(int)' cannot be overloaded
   void print(int n) {
		^~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:478:8: error: with 'void a21::PCD8544Console<lcd, font>::print(int)'
   void print(FlashStringPtr str) {
		^~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:515:16: error: 'FlashStringPtr' has not been declared
   void println(FlashStringPtr str) {
				^~~~~~~~~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:520:8: error: 'void a21::PCD8544Console<lcd, font>::println(int)' cannot be overloaded
   void println(int n) {
		^~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/pcd8544.hpp:515:8: error: with 'void a21::PCD8544Console<lcd, font>::println(int)'
   void println(FlashStringPtr str) {
		^~~~~~~
In file included from /Users/<user>/Documents/Arduino/libraries/a21-master/a21.hpp:18:0,
				 from /Users/<user>/NoiseChip/NoiseChip.ino:18:
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:38:20: error: 'FlashStringPtr' has not been declared
  static void print(FlashStringPtr str) {
					^~~~~~~~~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:46:14: error: 'static void a21::Print<T>::print(int)' cannot be overloaded
  static void print(int n) {
			  ^~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:38:14: error: with 'static void a21::Print<T>::print(int)'
  static void print(FlashStringPtr str) {
			  ^~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:75:22: error: 'FlashStringPtr' has not been declared
  static void println(FlashStringPtr str) {
					  ^~~~~~~~~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:80:14: error: 'static void a21::Print<T>::println(int)' cannot be overloaded
  static void println(int n) {
			  ^~~~~~~
/Users/<user>/Documents/Arduino/libraries/a21-master/a21/print.hpp:75:14: error: with 'static void a21::Print<T>::println(int)'
  static void println(FlashStringPtr str) {
			  ^~~~~~~
exit status 1

[aleh]

@kurogedelic Hey, thanks for reporting again!

The NoiseChip indeed fails to build for the ATtiny board definition that you are using. It turns out that Digispark (that I was targeting for ATtiny projects) has a different idea of program space string type, while yours follows the regular Arduino way. I've corrected that definition to be used only for Digispark boards, not every time an ATtiny is involved. Please pull and try building again.

Thanks!

[aleh]

@kurogedelic Hey! Did you have a chance to test this again perhaps?

[kurogedelic]

@aleh
I'm sorry to have you waiting.
The compilation was passed successfully.
And that works fine on my ATtiny.
Thanks for your great program.

[aleh]

Glad to hear it works! Thanks a lot!