HP SunSoft Pascal 4.0 - Manual (Page 267)

Math Libraries 243
11
The syntax of this function is described in the ieee_flags (3M) man page.
If an exception is raised at any time during program execution, then its flag is
set, unless it is explicitly cleared. Clearing accrued exceptions is done by a call,
as shown in the following Pascal program.
program TestIEEEFlags(output);
#include "math_p.h"
var
FlAction, FlMode, FlIn: string;
FlOut: string_pointer;
Zero: integer := 0;
begin
writeln(sqr(-1)); { Invalid operation }
writeln(1 / Zero); { Division by zero }
writeln(exp(709.8)); { Overflow }
writeln(exp(-708.5)); { Underflow }
writeln(log(1.1)); { Inexact }
FlAction := 'clear';
FlMode := 'exception';
FlIn := 'all';
writeln(ieee_flags(FlAction, FlMode, FlIn, FlOut));
end.