Neophyte's question raised re: pcc problem

[Chip Rosenthal]

>   From: keashly at mprvaxa.UUCP (Lance Keashly)
>
>   m(){
>   int a,b,c;
>   { 
>     /* case 2 ideally "a" should have the same value after but pcc
>     interprets them differently (K&R say that it is OK 185) */
>     if ( a = b++ + b );
>     a = b++ + b;
>     }

Anybody want to handle a question I have about the above?  It has
never been clear to me what an expression like "a = b++ + b" 
evaluates to, i.e. would the right-hand addend be the value before 
or after the incrementation?  Is the answer to this compiler/machine
dependant?  (Mailing a response is probably preferable to posting.)
Thanks.

  Chip Rosenthal, Intel/Santa Clara
  {pur-ee,hplabs,ucbvax!amd70,ogcvax!omsvax}!intelca!t4test!chip