I2CEeprom ARMC6 compilation failed with mbed-os master

[jeromecoutant]

Hi

Due to new MBED compilation options, I2CEeprom can't be compiled any more...

[Error] I2CEeprom.cpp@32,23: non-constant-expression cannot be narrowed from type 'std::size_t' (aka 'unsigned int') to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@32,39: non-constant-expression cannot be narrowed from type 'unsigned int' to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@47,23: non-constant-expression cannot be narrowed from type 'std::size_t' (aka 'unsigned int') to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@47,39: non-constant-expression cannot be narrowed from type 'unsigned int' to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@62,23: non-constant-expression cannot be narrowed from type 'std::size_t' (aka 'unsigned int') to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@62,39: non-constant-expression cannot be narrowed from type 'unsigned int' to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@101,27: non-constant-expression cannot be narrowed from type 'std::size_t' (aka 'unsigned int') to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@101,43: non-constant-expression cannot be narrowed from type 'unsigned int' to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@161,27: non-constant-expression cannot be narrowed from type 'std::size_t' (aka 'unsigned int') to 'char' in initializer list [-Wc++11-narrowing]
[Error] I2CEeprom.cpp@161,43: non-constant-expression cannot be narrowed from type 'unsigned int' to 'char' in initializer list [-Wc++11-narrowing]

[jeromecoutant]

@MarceloSalazar @c1728p9

[MarceloSalazar]

@jeromecoutant thanks for reporting this. I confirm I see this issue when trying 5.13.0-rc2 but not when using 5.12.4

@ARMmbed/mbed-os-maintainers can you please have a look? It looks some flags have been added recently which break compatibility applications/tests such this one.

[adbridge]

@MarceloSalazar is this an officially supported compatibility test? I haven't seen this before and I suspect it is not run in CI ?

[adbridge]

The only obvious change I can see which might impact is this one https://github.com/ARMmbed/mbed-os/pull/10427 , though I don't know what the impact is. I will ask @kjbracey-arm could you take a look please ?

[kjbracey]

This would be https://os.mbed.com/users/mbed_official/code/I2CEeprom/ - discussed it with @0xc0170 , but neither of us have taken action. I'm not sure who's supposed to be responsible for that.

The code is not C++11 compatible - there's a new C++11 rule that you can't have narrowing conversions in initialiser lists. Conversions that might change the value are barred unless the compiler can see that they're a constant expression that doesn't.

This rule only applies to {} initialiser lists, not any other parameter passing or assignment.

So:

  uint32_t x;
  void foo(uint8_t x);
  foo(x); // OK
  foo(x & 0xFF); // OK
  uint8_t array1[] = { x }; // not OK in C++11
  uint8_t array2[] = { x & 0xFF }; // not OK in C++11
  uint8_t array3[] = { 0x100 }; // not OK in C++11
  uint8_t array4[] = { 0x100 & 0xFF } ; // OK
  uint8_t array5[] = { static_cast<uint8_t>(x) }; // OK
  uint8_t array6[] = { (uint8_t) x }; // OK
  uint32_t value1 = { -1 } ; // not OK in C++11
  uint32_t value2 = -1; // OK

[0xc0170]

This would be https://os.mbed.com/users/mbed_official/code/I2CEeprom/ - discussed it with @0xc0170 , but neither of us have taken action. I'm not sure who's supposed to be responsible for that.

This should be fixed. @donatieng Would be anyone from HAL team to able to help to fix this repository ?

[MarceloSalazar]

@donatieng bump

[MarceloSalazar]

Internal reference: IOTHAL-508

[jeromecoutant]

patch: https://github.com/ARMmbed/ci-test-shield/pull/91

[jeromecoutant]

@mtomczykmobica