Fix return type of ArduinoLEDMatrix::begin()

[mast-eu]

While playing around with the LED matrix on my Arduino R4 WiFi I noticed that the function ArduinoLEDMatrix::begin() causes a compiler warning:

(This is what I observe after setting Preferences -> Compiler Warnings to All)

The reason appears to be very simple: ArduinoLEDMatrix::begin() is declared to return an int, but never returns anything. I think this is actually ok, since the function has nothing useful it could return.
Thus I send you this PR to change it's return type from int to void.

[CLAassistant]

All committers have signed the CLA.

[facchinm]

Hi @mast-eu ,
I'd prefer to keep the int return and return 1 if the timer was correctly started, 0 otherwise to be coherent with the usual semantic of begin().
Would you mind amending the PR in this way?

[facchinm]

Could supersede #225

[mast-eu]

Yes, I can amend the PR. But why do you want to keep int? Shouldn't bool be the better choice?
I'm looking for some examples of begin() in the code and came across

ArduinoCore-renesas/cores/arduino/FspTimer.cpp

Line 64 in aee54e9

bool FspTimer::begin(timer_mode_t mode, uint8_t tp, uint8_t channel, uint32_t period_counts, uint32_t pulse_counts, timer_source_div_t sd, GPTimerCbk_f cbk /*= nullptr*/ , void *ctx /*= nullptr*/ ) {

or

ArduinoCore-renesas/cores/arduino/pwm.cpp

Line 41 in aee54e9

bool PwmOut::begin() {

[facchinm]

bool is fine too, I'd just avoid the signature change but there's no strong reason 🙂

[mast-eu]

@facchinm Please have a look. I've changed the implementation to provide a meaningful return value.

I preferred bool over int, because maybe it's just me, but with int I'd expect 0 to indicate that everything is ok and any non zero value to be an error code. While with bool it's exactly the other way.

[facchinm]

Super, looks much better now! Merging

[misaz]

I think this change was incorect because of using bool type. Data type of begin() is actually important because begin() of ArduinoLEDMatrix overrides begin() of ArduinoGraphics and ArduinoGraphics define begin as virtual int begin(); (https://github.com/arduino-libraries/ArduinoGraphics/blob/master/src/ArduinoGraphics.h#L41), so overriding it with method with bool output type naturally ends up with mismatch output type compiler error.

In file included from C:\Users\michal\AppData\Local\Temp\.arduinoIDE-unsaved2024411-121224-1myqqzw.l57b\TextWithArduinoGraphics\TextWithArduinoGraphics.ino:3:0:
C:\Users\michal\AppData\Local\Arduino15\packages\arduino\hardware\renesas_uno\1.1.0\libraries\Arduino_LED_Matrix\src/Arduino_LED_Matrix.h:172:10: error: conflicting return type specified for 'virtual bool ArduinoLEDMatrix::begin()'
     bool begin() {
          ^~~~~
In file included from C:\Users\michal\AppData\Local\Temp\.arduinoIDE-unsaved2024411-121224-1myqqzw.l57b\TextWithArduinoGraphics\TextWithArduinoGraphics.ino:2:0:
c:\Users\michal\Documents\Arduino\libraries\ArduinoGraphics\src/ArduinoGraphics.h:41:15: error:   overriding 'virtual int ArduinoGraphics::begin()'
   virtual int begin();
               ^~~~~