Re: nested unnamed structs/unions broken?

[Jim Wilson <wilson at specifixinc dot com>]

Steve Watt wrote:
> union optid {
>     unsigned int opcode_tid;
>     struct {
>         unsigned int opcode:8;
>         unsigned int tid:24; 
>     };
> };

You now need the -fms-extensions option in order for gcc to accept this. 
 This feature was originally added because it was used in MS Windows 
header files, and was thus needed by cygwin.  Some people objected to 
the feature when it accidentally turned up in other places, so now it 
only gets enabled if you explicitly ask for MSC compatibility.

There is one case that gcc continues to accept by default, because it 
was agreed to be generally useful.  This is the case of a union inside a 
struct, where the union has no type name and no field name.  This is the 
case documented in the gcc manual in the Unnamed Fields node.
http://gcc.gnu.org/onlinedocs/gcc-3.3.1/gcc/Unnamed-Fields.html#Unnamed%20Fields
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com