Question

I have this strange issue:

When I create an enum like this:

typedef enum {    
    kParcelStatusInTransit,
    kParcelStatusArrived,
    kParcelStatusDelivered,
    kParcelStatusUnknown
} ParcelStatus;

I get an error: expected identifier before numeric constant

When I add even the smallest change to the members name, I get no error:

typedef enum {    
    kChangeParcelStatusInTransit,
    kChangeParcelStatusArrived,
    kChangeParcelStatusDelivered,
    kChangeParcelStatusUnknown
} ParcelStatus;

How is this possible? What numeric constant is the error talking about? It makes no sense to me…

Answer 1

One of the constants has been #defined in another file. Because of this, the preprocessor replaces the identifier in the enum with its value. The compiler then sees this constant value and complains, since it expected an identifier.