Re: Compile prob. with gpc20050217 - Gpc

24 Feb 2005


      Apologies for the limited code detail earlier.  It appears the offending bit
is the use of a constant array index.  Here is a short program which
reproduces the bug:
PROGRAM arr_test(input,output);
TYPE arrtype = ARRAY [-10..10] OF double;
VAR  test : arrtype;
PROCEDURE init(VAR arr: arrtype);
  VAR i : integer;
  BEGIN
     FOR i:= -10 TO 10 DO arr[i]:= i*2.0;
     i:= 0; arr[i]:= 1.0; { This is OK, using i for the index }
     arr[0]:= 1.0; { This causes an arithmetical error at compile time }
  END;
BEGIN
   init(test);
END.
...
-----Original Message-----
From: Waldek Hebisch [mailto:hebisch@math.uni.wroc.pl]
Sent: 19 February 2005 04:50
To: Wood David
Subject: Re: Compile prob. with gpc20050217
...
I'm getting a new compile time error (error: arithmetical overflow )
with
...
this previously ok bit of code:
     FOR I := -Clutter_max_width TO Clutter_max_width DO

        Spectral_purity[I] := Spec_purity_level / (1 + (SQR(I) /

Width_sqrd));
     Spectral_purity[0] := 1;


All the variables and arrays use type double, except i which is an
integer.
...
The error is reported at the last code line, but I guess it may stem
from
...
the previous line.
I don't understand why gpc should report an arithmetic overflow error at
compile-time.  This is normally a run-time error!
That is too little detail to reproduce the problem. gpc computes many
constant expressions at compile-time and signals error in case of
overflow. So in particular values of your constants are crucial.
In general you should make sure that you give a _complete_ program
which reproduces the problem.
--
                              Waldek Hebisch
hebisch@math.uni.wroc.pl
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