generalized lvalues -- patch outline

[Eric Botcazou]

> I haven't looked at that list, but one data point: CW restricts this
> cast to pointers, so that's good enough for CW compatibility.  I guess
> we learned just today (thanks, Eric!) that Solaris supports some
> version of this extension, at least for C.  We don't yet know the
> boundaries of Sun's version of the extension.

Since you so kindly asked... :-)

Sun seems to restrict it to pointers too, i.e. it rejects (short)v = 1 as well 
as:

void bar(unsigned long addr)
{
  *((int *)addr)++ = 1;
}

with:
"ext.c", line 8: a cast does not yield an lvalue
cc: acomp failed for ext.c


Here's the reaction of the C++ compiler:
poog% cat ext.C
void foo(char *p)
{
  *((long *) p)++ = 1;
}
poog% CC -S ext.C
"ext.C", line 3: Error: Operand for operator "++" must be an lvalue.
1 Error(s) detected.

-- 
Eric Botcazou