Date: Fri, 9 Jul 1999 00:06:40 -0400 (EDT) From: "John W. DeBoskey" <jwd@unx.sas.com> To: freebsd-hackers@freebsd.org Subject: sigaction inconsistancy (here I go again) Message-ID: <199907090406.AAA10435@bb01f39.unx.sas.com>
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Hi,
Running -current...
I'm trying to verify SIGFPE handling and am finding some
interesting issues. In the following test program, a divide
by zero is done and the SIGFPE delivered.
$ ./fp
sig == 8
code== 0
z has the value 1.000000
It seems that from <machine/trap.h> the value of code should
have been:
/* codes for SIGFPE/ARITHTRAP */
#define FPE_FLTDIV_TRAP 0x3 /* floating/decimal divide by zero */
ie: 3 and not 0.
Also, I haven't gone into the code yet, but the floating point
registers are not saved into the sigcontext so that they can be
inspected and modified as appropriate.
Thanks,
John
ps: I also noted that SA_RESTART is not documented in the man page
with the other mask bits, but instead is mentioned in a follow-on
statement. Just slightly misleading.
--------------------------------------------------------------------------
#include <stdio.h>
#include <floatingpoint.h>
#include <signal.h>
void fphand(int sig, int code, struct sigcontext *scp)
{
fprintf(stderr,"sig == %d\n",sig);
fprintf(stderr,"code== %d\n",code);
return;
}
void
setup()
{
int rc;
struct sigaction act, oact;
act.sa_handler = &fphand;
act.sa_mask = 0;
act.sa_flags = SA_RESTART; /* not doc'd in man page */
rc = sigaction(SIGFPE, &act, &oact);
if (rc) {
perror("sigaction");
exit(1);
}
return;
}
double
doit(double x, double y)
{
return(x / y);
}
int
main()
{
double x,y,z;
fp_except_t mask = FP_X_DZ;
setup();
fpsetmask(mask);
x = 1.0;
y = 0.0;
z = doit(x,y);
printf("z has the value %f\n",z);
return((int) z);
}
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