Fix integer warnings

[Rotzbua]

e.g.:
LoRaDuplex.ino:47:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

[sandeepmistry]

@Rotzbua thanks for submitting, what board are you building for?

When I compile for Arduino Uno on IDE 1.8.5 I don't see any warnings.

[Rotzbua]

I usually switch the arduino ide to the highest warning level, then you will get the warning.

The (byte)LoRa.read is just for sanity, because int type is returned and do not fit into byte.

[sandeepmistry]

I usually switch the arduino ide to the highest warning level, then you will get the warning.

Thanks I missed that, for the Uno I now get (without this PR):

/Users/smistry/Documents/Arduino/libraries/LoRa/examples/LoRaDuplex/LoRaDuplex.ino: In function 'void loop()':
/Users/smistry/Documents/Arduino/libraries/LoRa/examples/LoRaDuplex/LoRaDuplex.ino:47:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (millis() - lastSendTime > interval) {
                               ^

The (byte)LoRa.read is just for sanity, because int type is returned and do not fit into byte.

@tigoe any feedback on those changes? Do you think casting to byte is unfriendly to beginners?

[Floessie]

Do you think casting to byte is unfriendly to beginners?

Those explicit casts to byte on assignment aren't necessary. So the question shouldn't arise. Just my 2¢.

Best,
Flössie

[Rotzbua]

Normaly I use clion, it always warns about implicit type conversation. Implicit type conversations are often reasons for bugs, so I personally do not like them.

It seems that -Wall do not include -Wconversion to enable the warning.

[Floessie]

Implicit type conversations are often reasons for bugs, so I personally do not like them.

Fair enough.

It seems that -Wall do not include -Wconversion to enable the warning.

That's for a reason. Quoting:

Implicit conversions are very common in C. This tied with the fact that there is no data-flow in front-ends (see next question) results in hard to avoid warnings for perfectly working and valid code. Wconversion is designed for a niche of uses (security audits, porting 32 bit code to 64 bit, etc.) where the programmer is willing to accept and workaround invalid warnings. Therefore, it shouldn't be enabled if it is not explicitly requested.