diff --git a/C/sysbits.c b/C/sysbits.c
index 79d8c142a..6401ae225 100644
--- a/C/sysbits.c
+++ b/C/sysbits.c
@@ -1492,19 +1492,25 @@ ReceiveSignal (int s)
     case SIGKILL:
       Yap_Error(INTERRUPT_ERROR,MkIntTerm(s),NULL);
 #endif
-#if defined(SIGUSR1)
+#ifdef SIGUSR1
     case SIGUSR1:
       /* force the system to creep */
       Yap_signal (YAP_USR1_SIGNAL);
       break;
 #endif /* defined(SIGUSR1) */
-#if defined(SIGUSR2)
+#ifdef SIGUSR2
     case SIGUSR2:
       /* force the system to creep */
       Yap_signal (YAP_USR2_SIGNAL);
       break;
 #endif /* defined(SIGUSR2) */
-#if defined(SIGHUP)
+#ifdef SIGPIPE
+    case SIGPIPE:
+      /* force the system to creep */
+      Yap_signal (YAP_PIPE_SIGNAL);
+      break;
+#endif /* defined(SIGPIPE) */
+#ifdef SIGHUP
     case SIGHUP:
       /* force the system to creep */
       Yap_signal (YAP_HUP_SIGNAL);
@@ -1545,6 +1551,9 @@ InitSignals (void)
     my_signal (SIGHUP,  ReceiveSignal);
     my_signal (SIGALRM, HandleALRM);
 #endif
+#ifdef SIGPIPE
+    my_signal (SIGPIPE, ReceiveSignal);
+#endif
 #if _MSC_VER || defined(__MINGW32__)
     signal (SIGINT, SIG_IGN);
     SetConsoleCtrlHandler(MSCHandleSignal,TRUE);
@@ -2543,6 +2552,11 @@ p_first_signal(void)
     UNLOCK(SignalLock);
     return Yap_unify(ARG1, MkAtomTerm(Yap_LookupAtom("sig_usr1")));
   }
+  if (ActiveSignals & YAP_PIPE_SIGNAL) {
+    ActiveSignals &= ~YAP_PIPE_SIGNAL;
+    UNLOCK(SignalLock);
+    return Yap_unify(ARG1, MkAtomTerm(Yap_LookupAtom("sig_pipe")));
+  }
   if (ActiveSignals & YAP_HUP_SIGNAL) {
     ActiveSignals &= ~YAP_HUP_SIGNAL;
     UNLOCK(SignalLock);
diff --git a/H/Yap.h b/H/Yap.h
index 9b60fa6ae..2862dc458 100644
--- a/H/Yap.h
+++ b/H/Yap.h
@@ -10,7 +10,7 @@
 * File:		Yap.h.m4						 *
 * mods:									 *
 * comments:	main header file for YAP				 *
-* version:      $Id: Yap.h,v 1.36 2008-05-15 13:41:46 vsc Exp $	 *
+* version:      $Id: Yap.h,v 1.37 2008-05-23 10:02:13 vsc Exp $	 *
 *************************************************************************/
 
 #include "config.h"
@@ -573,7 +573,8 @@ typedef enum
   YAP_STACK_DUMP_SIGNAL = 0x4000,	/* received stack dump signal */
   YAP_STATISTICS_SIGNAL = 0x8000,	/* received statistics */
   YAP_DELAY_CREEP_SIGNAL = 0x10000,	/* received a creep but should not do it */
-  YAP_AGC_SIGNAL = 0x20000	/* call atom garbage collector asap */
+  YAP_AGC_SIGNAL = 0x20000,	/* call atom garbage collector asap */
+  YAP_PIPE_SIGNAL = 0x40000	/* call atom garbage collector asap */
 } yap_signals;
 
 #define NUMBER_OF_YAP_FLAGS  LAST_FLAG
diff --git a/changes-5.1.html b/changes-5.1.html
index 2c9461765..7f5a1ad4c 100644
--- a/changes-5.1.html
+++ b/changes-5.1.html
@@ -17,6 +17,8 @@ xb
 
 <h2>Yap-5.1.3:</h2>
 <ul>
+<li> FIXED: handle SIGPIPE and improve USR1 and USR2 (obs from Nicos
+Angelopoulos).</li>
 <li> NEW: tmp_file/2 (request from Nicos Angelopoulos).</li>
 <li> FIXED: too much pruning on predicate_property/2 (obs from Nicos
 Angelopoulos).</li>
diff --git a/pl/messages.yap b/pl/messages.yap
index be8bd335d..ec2a29743 100644
--- a/pl/messages.yap
+++ b/pl/messages.yap
@@ -11,7 +11,7 @@
 * File:		utilities for displaying messages in YAP.		 *
 * comments:	error messages for YAP					 *
 *									 *
-* Last rev:     $Date: 2008-05-15 13:41:47 $,$Author: vsc $						 *
+* Last rev:     $Date: 2008-05-23 10:02:13 $,$Author: vsc $						 *
 *									 *
 *									 *
 *************************************************************************/
@@ -243,6 +243,8 @@ system_message(error(resource_error(threads), Where)) -->
 	[ 'RESOURCE ERROR- too many open threads' - [Where] ].
 system_message(error(resource_error(memory), Where)) -->
 	[ 'RESOURCE ERROR- not enough virtual memory' - [Where] ].
+system_message(error(signal(SIG,_), _)) -->
+	[ 'UNEXPECTED SIGNAL: ~a' [SIG] ].
 system_message(error(syntax_error(G,0,Msg,[],0,0), _)) -->
 	[ 'SYNTAX ERROR: ~a' - [G,Msg] ].
 system_message(error(syntax_error(_,_,_,Term,Pos,Start), Where)) -->
diff --git a/pl/signals.yap b/pl/signals.yap
index e6d8a0153..0d2100d3f 100644
--- a/pl/signals.yap
+++ b/pl/signals.yap
@@ -72,6 +72,8 @@
 	'$signal_handler'(sig_usr1, G).
 '$do_signal'(sig_usr2, G) :-
 	'$signal_handler'(sig_usr2, G).
+'$do_signal'(sig_pipe, G) :-
+	'$signal_handler'(sig_pipe, G).
 
 '$signal_handler'(Sig, [M|G]) :-
 	'$signal_do'(Sig, Goal),
@@ -122,8 +124,9 @@
 		      ( exists('~/.prologrc') -> [-'~/.prologrc'] ; true ),
 		      ( exists('~/prolog.ini') -> [-'~/prolog.ini'] ; true ))).
 % die on signal default.
-'$signal_def'(sig_usr1, (print_message(error, 'Received user signal 1'),halt)).
-'$signal_def'(sig_usr2, (print_message(error, 'Received user signal 2'),halt)).
+'$signal_def'(sig_usr1, throw(error(signal(usr1,[]),true))).
+'$signal_def'(sig_usr2, throw(error(signal(usr2,[]),true))).
+'$signal_def'(sig_pipe, throw(error(signal(pipe,[]),true))).
 % ignore sig_alarm by default
 '$signal_def'(sig_alarm, true).