BUG: gpc and type modifiers.

Thu, 3 Oct 96 14:53:43 CST

I discovered a bug in the way GPC treats type modifiers:

Consider this snippet, for a 32bit architecture:

-------------------------------------------

type
  uint = __unsigned__ integer;  { unsigned 32-bit }

const
  c1 : uint = $7FFFFFFF ;       { maxint }
  c2 : uint = $80000000 ;

-------------------------------------------

The declaration of c2 gives this error message:
        `integer constant does not fit in integer type'

while this faulty snippet is accepted:

-------------------------------------------

type
  short = __short__ integer;    { signed 16-bit }

const
  c3 : short = $FFFF ;
  c4 : short = $00010000 ;

-------------------------------------------

Although c4 gives a warning:
        `warning: overflow in implicit constant conversion'

Obviously, GPC doesn't treat the type modifiers the right way when it
evaluates whether a constant is valid or not.

The same is true for __longlong__ (64bit), which cannot be initialized
with a value > $7FFFFFFF.

Workaround
==========
With this silly trick it's still possible to assign an unsigned 32bit
value:

-------------------------------------------

type
  uint = __unsigned__ integer;  { unsigned 32-bit }

const
  c1 : uint = $7FFFFFFF + 1;

-------------------------------------------
This gives again:
        `warning: overflow in implicit constant conversion'

which can be suppressed by surrounding the declaration with {$W-} .. {$W+}

JanJaap

---
"Nothing shocks me, I'm a scientist", Indiana Jones

J.J. van der Heijden (j.j.vanderheijden@student.utwente.nl)