"Incomplete type" and "redefinition" errors in gcc

[Richard Earnshaw]

> Hi,
> 
> If I compile the following simple C code with gcc:
> ________________try.c________________________
> 
> typedef enum VIDF VIDF;
> typedef unsigned int U32;
> typedef unsigned int U32;
> 
> typedef struct VIDR
> {
>   VIDF VidF;
>   U32  width;
> } VIDR;
> 
> typedef enum VIDF
> {
>   aVIDF,
>   bVIDF
> } VIDF;
> 
> int main( void )
> {
>   return 0;
> }
> ____________________________________________
> 
> I get the following errors:
> 
> bash-2.05b$ gcc try.c
> try.c:3: error: redefinition of `U32'
> try.c:2: error: `U32' previously declared here
> try.c:7: error: field `VidF' has incomplete type
> try.c:15: error: redefinition of `VIDF'
> try.c:1: error: `VIDF' previously declared here

All of these diagnostics are correct.   You can't repeat typedefs, and you 
can't instantiate a forward declaration of an enum.

R.