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Placing suffix u with unsigned variables

I was reading on misra website that for assigning 0 to unsigned variable, 'u' must be suffixed.

For example:

uint8_t my_cnt = 0U;

1. Does that even on declaring array I should use this.Like

uint8_t my_arr[10U];

2. Also while using switch cases like:

void func(uint8_t no)
{
    switch(no)
    {
         case 1U:
         break;

         case 2U:
         break;

    }
}

If yes then what if variable passed to switch is of int8_t type. In above example if

int8_t no;

Parents

0 B 4 over 11 years ago in reply to B 4

Taken from document "MISRA-C:2004 Guidelines for the use of the C language in critical systems"


Rule 10.6 (required): A “U” suffix shall be applied to all constants of unsigned type.

The type of an integer constant is a potential source of confusion, because it is dependent on a
complex combination of factors including:

  The magnitude of the constant
  The implemented sizes of the integer types
  The presence of any suffixes
  The number base in which the value is expressed (i.e. decimal, octal or hexadecimal).

and


Signedness of constants should be explicit. Consistent signedness is an important principle
in constructing well formed expressions. If a constant is of an unsigned type, it is helpful
to avoid ambiguity by applying a “U” suffix. When applied to larger values, the suffix may
be redundant (in the sense that it does not influence the type of the constant); however
its presence is a valuable contribution towards clarity.

I never liked the look of Misra anyway.

Reply

0 B 4 over 11 years ago in reply to B 4

Taken from document "MISRA-C:2004 Guidelines for the use of the C language in critical systems"


Rule 10.6 (required): A “U” suffix shall be applied to all constants of unsigned type.

The type of an integer constant is a potential source of confusion, because it is dependent on a
complex combination of factors including:

  The magnitude of the constant
  The implemented sizes of the integer types
  The presence of any suffixes
  The number base in which the value is expressed (i.e. decimal, octal or hexadecimal).

and


Signedness of constants should be explicit. Consistent signedness is an important principle
in constructing well formed expressions. If a constant is of an unsigned type, it is helpful
to avoid ambiguity by applying a “U” suffix. When applied to larger values, the suffix may
be redundant (in the sense that it does not influence the type of the constant); however
its presence is a valuable contribution towards clarity.

I never liked the look of Misra anyway.

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