From cd147bc3e6bb999893c379c58a7042bf311a2e5c Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Tue, 2 Jul 2002 12:24:48 +0000
Subject: [PATCH] [project @ 2002-07-02 12:24:48 by simonmar] Don't install a
 SIGFPE handler: this causes us to go into an infinite loop
 on a divide by zero on some systems (BSD, but not Linux it
 seems).  I don't think we really ought to be ignoring
 SIGFPE: for floating point exceptions, the system usually
 has a way to request that operations generate exceptional
 values rather than signals (this is the required IEEE
 behaviour), and for integral division we should really
 check beforehand for division by zero (we don't yet).

---
 ghc/rts/Signals.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/ghc/rts/Signals.c b/ghc/rts/Signals.c
index 9edefbb..b94ad6d 100644
--- a/ghc/rts/Signals.c
+++ b/ghc/rts/Signals.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Signals.c,v 1.24 2002/03/26 23:51:27 sof Exp $
+ * $Id: Signals.c,v 1.25 2002/07/02 12:24:48 simonmar Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -363,12 +363,24 @@ initDefaultHandlers()
     }
 
     // install the SIGFPE handler
+
+    // In addition to handling SIGINT, also handle SIGFPE by ignoring it.
+    // Apparently IEEE requires floating-point exceptions to be ignored by
+    // default, but alpha-dec-osf3 doesn't seem to do so.
+
+    // Commented out by SDM 2/7/2002: this causes an infinite loop on
+    // some architectures when an integer division by zero occurs: we
+    // don't recover from the floating point exception, and the
+    // program just generates another one immediately.
+#if 0
     action.sa_handler = SIG_IGN;
     sigemptyset(&action.sa_mask);
     action.sa_flags = 0;
     if (sigaction(SIGFPE, &action, &oact) != 0) {
 	prog_belch("warning: failed to install SIGFPE handler");
     }
+#endif
+
 #ifdef alpha_TARGET_ARCH
     ieee_set_fp_control(0);
 #endif
-- 
1.7.10.4