force new enums for pinMode and pinStatus to 8 bits type instead of default int

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
18/100
Issue type
Refactor
Clarity
Needs clarification
Activity status
Stale
Domain
embedded-iot

Research direction

Start by finding the PinMode and PinStatus enum declarations in the ArduinoCore-API API, then assess the source- and binary-compatibility consequences across existing Arduino code. Done requires a project decision on whether the proposed uint8_t underlying types are acceptable; the issue itself recommends against production adoption.

Written by the indexing model from the issue text.

Description

I've seen

typedef enum {
  LOW     = 0,
  HIGH    = 1,
  CHANGE  = 2,
  FALLING = 3,
  RISING  = 4,
} PinStatus;

typedef enum {
  INPUT           = 0x0,
  OUTPUT          = 0x1,
  INPUT_PULLUP    = 0x2,
  INPUT_PULLDOWN  = 0x3,
} PinMode;

This will let the compiler decide how big the backend storage needs to be for those, and it will default to an int (16 or 32 bit depending on architecture). There is no need for this waste of memory and it prevents also some compiler optimization

I suggest forcing the uint8_t type, 256 values should be plenty to represent a pinMode or a pinStatus..

proposed changes:

typedef enum : uint8_t  {
  LOW     = 0,
  HIGH    = 1,
  CHANGE  = 2,
  FALLING = 3,
  RISING  = 4,
} PinStatus;

typedef enum : uint8_t {
  INPUT           = 0x0,
  OUTPUT          = 0x1,
  INPUT_PULLUP    = 0x2,
  INPUT_PULLDOWN  = 0x3,
} PinMode;

but in practice I would vote against getting these changes in production. There is no value added and tons of unwanted consequences for existing code out there to make this worthwhile.

Dominant language
C++
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Forks
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