Question

I currently have code with an enum where one value is set and the rest are left to be set by the compiler using the previous value +1, or so I hope.

Is this functionality within an enumerated type compiler dependant, an example is below to clarify.

enum FUNC_ERROR_CODE    
{
    FUNC_SUCCESS,
    FUNC_ERROR_1 = 24,
    FUNC_ERROR_2,
    FUNC_ERROR_3
}

Is it safe to assume that FUNC_ERROR_2 will have the value 25 and FUNC_ERROR_3 will have the value 26, regardless of compliler used.

I’m coding this so as a function can return an integer value, 0 is always success and any other value can signify failure.

Answer 1

It is safe to assume that:

• Enumeration Declaration [dcl.enum]
  

  The identifiers in an enumerator-list are declared as constants, and can appear wherever constants are
  required. An enumerator-definition with = gives the associated enumerator the value indicated by the
  constant-expression. The constant-expression shall be of integral or enumeration type. If the first
  enumerator has no initializer, the value of the corresponding constant is zero. An enumerator-definition
  without an initializer gives the enumerator the value obtained by increasing the value of the previous enumerator by one.

But if you have a typesafe enum: Use it! Don’t fall back on converting to/from integers.