I don't know if this is a bug in gcc or the glibc... Consider the
following program "traps1":
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <float.h>
#include <fenv.h>
int main (int argc, char *argv[])
{
volatile long double x, y = 0.0;
if (argc != 3)
{
fprintf (stderr, "Usage: exception <double> <flag>\n");
exit (1);
}
if (fesetround (FE_DOWNWARD))
{
fprintf (stderr, "Can't set rounding mode to FE_DOWNWARD\n");
exit (1);
}
x = atof (argv[1]);
x *= LDBL_MAX;
printf ("x = %Lg\n", x);
feenableexcept (FE_OVERFLOW);
if (atoi (argv[2]))
y += 0.0;
return 0;
}
I get the following results on X86 and PowerPC processors with gcc 4.0
(Debian):
* x86, traps1 2 0 -> x = 1.18973e+4932
* x86, traps1 2 1 -> ditto with floating point exception signal
* ppc, both cases -> x = 1.79769e+308 with FPE signal
I don't think one should get floating-point exception signals, and in
any case, the results between both processors seem to be inconsistent.
--
Vincent Lefèvre <[EMAIL PROTECTED]> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / SPACES project at LORIA
