diff --git a/library/mpi/examples/demo2.pl b/library/mpi/examples/demo2.pl
index a3272c5de..825bbf97f 100644
--- a/library/mpi/examples/demo2.pl
+++ b/library/mpi/examples/demo2.pl
@@ -30,7 +30,7 @@ do(0, Num) :-
 	format( "1 AA~n", [] ),
 	mpe_log(Ev1,0,event1),
 	format( "2 AA~n", [] ),
-	mpi_bcast( Num, 0, 100 ),
+	mpi_bcast( Num, 0 ),
 	format( 'Proc 0: broadcast ~q.~n', [Num] ),
 	mpe_log(Ev2,0,event2).
 do(Rank, _) :-
@@ -39,7 +39,7 @@ do(Rank, _) :-
 	mpe_create_event(Ev2),
 	format( "Ev1 == ~q, Ev2 == ~q~n", [Ev1,Ev2] ),
 	mpe_log(Ev1,0,event1),
-	mpi_bcast( Num, 0, 100 ),
+	mpi_bcast( Num, 0 ),
 	format( 'Proc ~q: had ~q broadcast from 0.~n', [Rank, Num] ),
 	mpe_log(Ev2,0,event2).
 
@@ -51,7 +51,13 @@ do(Rank, _) :-
 start(Msg) :-
 	mpi_open( Rank, NumProc, ProcName ),
 	format( 'Rank: ~q NumProc: ~q, ProcName: ~q~n', [Rank,NumProc,ProcName] ),
-	mpe_open,
+	(mpe_open -> true ;
+	    assert_static(mpe_create_event(dummy)),
+	    assert_static(mpe_create_state(_,_,_,_)),
+	    assert_static(mpe_log(_,_,_)),
+	    assert_static(mpe_close(_))
+	),
 	do(Rank, Msg),
 	format( 'Rank ~q finished!~n', [Rank] ),
 	mpe_close( demo2 ).
+
diff --git a/library/mpi/mpi.c b/library/mpi/mpi.c
index 99dbf0857..00d0f0953 100644
--- a/library/mpi/mpi.c
+++ b/library/mpi/mpi.c
@@ -9,14 +9,14 @@
 **************************************************************************
 *									 *
 * File:		mpi.c  							 *
-* Last rev:	$Date: 2002-03-13 09:01:39 $				 *
+* Last rev:	$Date: 2002-10-03 17:28:37 $				 *
 * mods:									 *
 * comments:	Interface to an MPI library                              *
 *									 *
 *************************************************************************/
 
 #ifndef lint
-static char *rcsid = "$Header: /Users/vitor/Yap/yap-cvsbackup/library/mpi/mpi.c,v 1.7 2002-03-13 09:01:39 stasinos Exp $";
+static char *rcsid = "$Header: /Users/vitor/Yap/yap-cvsbackup/library/mpi/mpi.c,v 1.8 2002-10-03 17:28:37 stasinos Exp $";
 #endif
 
 #include "Yap.h"
@@ -49,12 +49,15 @@ STATIC_PROTO (Int p_mpi_barrier, (void));
 static Int rank, numprocs, namelen;
 static char processor_name[MPI_MAX_PROCESSOR_NAME];
 
+/* used by the parser */
+static int StartLine;
+
 static Int mpi_argc;
 static char **mpi_argv;
 
 /* mini-stream */
 
-#define RECV_BUF_SIZE 4*1024
+#define RECV_BUF_SIZE 1024*32
 
 static size_t bufsize, bufstrlen;
 static char *buf;
@@ -63,17 +66,16 @@ static int bufptr;
 static void
 expand_buffer( int space )
 {
-
-#if 1
-  /* realloc has been SIGSEGV'ing on HP-UX 10.20.
-     do i need to look into arcane allignment issues? */
+#if MPI_AVOID_REALLOC
+  /*
+    realloc() has been SIGSEGV'ing on HP-UX 10.20, but there is
+    no problem in HP-UX 11.0. We can remove this bit here as soon
+    as Yap stops compiling on 10.20 anyway. If removed, also remove
+    the MPI_AVOID_REALLOC bits from configure.in and config.h.in
+  */
 
   char *tmp;
 
-#if 0
-  printf( "expanding by %d...", space );
-#endif
-
   tmp = malloc( bufsize + space );
   if( tmp == NULL ) {
     Error(SYSTEM_ERROR, TermNil, "out of memory" );
@@ -82,25 +84,23 @@ expand_buffer( int space )
   memcpy( tmp, buf, bufsize );
   free( buf );
   buf = tmp;
-#else
+#else /* use realloc */
   buf = realloc( buf, bufsize + space );
   if( buf == NULL ) {
-    Error(SYSTEM_ERROR, TermNil, "out of memory" );
+    Error(SYSTEM_ERROR, TermNil, "out of memory");
     exit_yap( EXIT_FAILURE );
   }
 #endif
 
   bufsize += space;
-
-#if 0
-  printf("SUCCESS\n");
-  printf( "New bufsize: %d\n", bufsize );
-#endif
 }
 
 static int
 mpi_putc(Int stream, Int ch)
 {
+#if 0
+  printf("%d: PUTC %d a.k.a. %c at %d\n", rank, ch, (char)ch, bufptr);
+#endif
   if( ch > 0 ) {
     if( bufptr >= bufsize ) expand_buffer( RECV_BUF_SIZE );
     buf[bufptr++] = ch;
@@ -111,6 +111,9 @@ mpi_putc(Int stream, Int ch)
 static Int
 mpi_getc(Int stream)
 {
+#if 0
+  printf("%d: GETC %c at %d\n", rank, buf[bufptr], bufptr);
+#endif
   return buf[bufptr++];
 }
 
@@ -123,6 +126,112 @@ mpi_eob(void)
 
 /* Term parser */
 
+static void
+clean_vars(VarEntry *p)
+{
+  if (p == NULL) return;
+  p->VarAdr = TermNil;
+  clean_vars(p->VarLeft);
+  clean_vars(p->VarRight);
+}
+
+static Term
+syntax_error (TokEntry * tokptr)
+{
+  Term info;
+  int count = 0, out = 0;
+  Int start, err = 0, end;
+  Term tf[6];
+  Term *error = tf+3;
+  CELL *Hi = H;
+
+  start = tokptr->TokPos;
+  clean_vars(VarTable);
+  clean_vars(AnonVarTable);
+  while (1) {
+    Term ts[2];
+
+    if (H > ASP-1024) {
+      H = Hi;
+      tf[3] = TermNil;
+      err = 0;
+      end = 0;
+      break;
+    }
+    if (tokptr == toktide) {
+      err = tokptr->TokPos;
+      out = count;
+    }
+    info = tokptr->TokInfo;
+    switch (tokptr->Tok) {
+    case Name_tok:
+      {
+	Term t0 = MkAtomTerm((Atom)info);
+	ts[0] = MkApplTerm(MkFunctor(LookupAtom("atom"),1),1,&t0);
+      }
+      break;
+    case Number_tok:
+      ts[0] = MkApplTerm(MkFunctor(LookupAtom("number"),1),1,&(tokptr->TokInfo));
+      break;
+    case Var_tok:
+      {
+	Term t[3];
+	VarEntry *varinfo = (VarEntry *)info;
+
+	t[0] = MkIntTerm(0);
+	t[1] = StringToList(varinfo->VarRep);
+	if (varinfo->VarAdr == TermNil) {
+	  t[2] = varinfo->VarAdr = MkVarTerm();
+	} else {
+	  t[2] = varinfo->VarAdr;
+	}
+	ts[0] = MkApplTerm(MkFunctor(LookupAtom("var"),3),3,t);
+      }
+      break;
+    case String_tok:
+      {
+	Term t0 = StringToList((char *)info);
+	ts[0] = MkApplTerm(MkFunctor(LookupAtom("string"),1),1,&t0);
+      }
+      break;
+    case Ponctuation_tok:
+      {
+	char s[2];
+	s[1] = '\0';
+	if (Ord (info) == 'l') {
+	  s[0] = '(';
+	} else  {
+	  s[0] = (char)info;
+	}
+	ts[0] = MkAtomTerm(LookupAtom(s));
+      }
+    }
+    if (tokptr->Tok == Ord (eot_tok)) {
+      *error = TermNil;
+      end = tokptr->TokPos;
+      break;
+    }
+    ts[1] = MkIntegerTerm(tokptr->TokPos);
+    *error =
+      MkPairTerm(MkApplTerm(MkFunctor(LookupAtom("-"),2),2,ts),TermNil);
+    error = RepPair(*error)+1;
+    count++;
+    tokptr = tokptr->TokNext;
+  }
+  tf[0] = MkApplTerm(MkFunctor(LookupAtom("read"),1),1,&ARG2);
+  {
+    Term t[3];
+    t[0] = MkIntegerTerm(start);
+    t[1] = MkIntegerTerm(err);
+    t[2] = MkIntegerTerm(end);
+    tf[1] = MkApplTerm(MkFunctor(LookupAtom("between"),3),3,t);
+  }
+  tf[2] = MkAtomTerm(LookupAtom("\n<==== HERE ====>\n"));
+  tf[4] = MkIntegerTerm(out);
+  tf[5] = MkIntegerTerm(err);
+  return(MkApplTerm(MkFunctor(LookupAtom("syntax_error"),6),6,tf));
+}
+
 static Term
 mpi_parse(void)
 {
@@ -176,14 +285,29 @@ mpi_parse(void)
 	}
       }
       TR = old_TR;
-      if (ErrorMessage)
-	YP_fprintf (YP_stderr, "%s", ErrorMessage);
-      else
-	syntax_error (tokstart);
-      YP_fprintf (YP_stderr, " ]\n");
-      
-      Error(SYSTEM_ERROR,TermNil,NULL);
-      return TermNil;
+      if (ParserErrorStyle == QUIET_ON_PARSER_ERROR) {
+	/* just fail */
+	return(FALSE);
+      } else if (ParserErrorStyle == CONTINUE_ON_PARSER_ERROR) {
+	ErrorMessage = NULL;
+	/* try again */
+	goto repeat_cycle;
+      } else {
+	Term terr = syntax_error(tokstart);
+	if (ErrorMessage == NULL)
+	  ErrorMessage = "SYNTAX ERROR";
+	
+	if (ParserErrorStyle == EXCEPTION_ON_PARSER_ERROR) {
+	  Error(SYNTAX_ERROR,terr,ErrorMessage);
+	  return(FALSE);
+	} else /* FAIL ON PARSER ERROR */ {
+	  Term t[2];
+	  t[0] = terr;
+	  t[1] = MkAtomTerm(LookupAtom(ErrorMessage));
+	  return(unify(MkIntTerm(StartLine = tokstart->TokPos),ARG4) &&
+		 unify(ARG5,MkApplTerm(MkFunctor(LookupAtom("error"),2),2,t)));
+	}
+      }
 
     } else {
       /* parsing succeeded */
@@ -279,20 +403,24 @@ p_mpi_send()             /* mpi_send(+data, +destination, +tag) */
   bufptr = 0;
   /* Turn the term into its ASCII representation */
   plwrite( t_data, mpi_putc, 5 );
-  bufstrlen = bufptr;
+  bufstrlen = (size_t)bufptr;
+
+  /* The buf is not NULL-terminated and does not have the
+     trailing ". " required by the parser */
+  mpi_putc( 0, '.' );
+  mpi_putc( 0, ' ' );
+
+  buf[bufptr] = 0;
+  bufstrlen = bufptr + 1;
   bufptr = 0;
 
-  while( bufstrlen-bufptr > 0 ) {
-    int n;
+  /* first send the size */
+  retv = MPI_Send( &bufstrlen, 1, MPI_INT, dest, tag, MPI_COMM_WORLD );
+  if( retv != MPI_SUCCESS ) return FALSE;
 
-    n = (bufstrlen-bufptr < RECV_BUF_SIZE)? (bufstrlen-bufptr) : RECV_BUF_SIZE;
-
-    /* Careful: the buf is not NULL-terminated and does not have the
-       trailing ". " required by the parser */
-    retv = MPI_Send( &buf[bufptr], n, MPI_CHAR, dest, tag, MPI_COMM_WORLD );
-    if( retv != 0 ) return FALSE;
-    bufptr += n;
-  }
+  /* and then the data */
+  retv = MPI_Send( &buf[bufptr], bufstrlen, MPI_CHAR, dest, tag, MPI_COMM_WORLD );
+  if( retv != MPI_SUCCESS ) return FALSE;
 
   return TRUE;
 }
@@ -333,40 +461,59 @@ p_mpi_receive()          /* mpi_receive(-data, ?orig, ?tag) */
   } else
     tag  = IntOfTerm( t_tag );
 
-  bufptr = 0;
-  while(TRUE) {
-    int n;
-
-    /* Receive the message as a C string */
-    retv = MPI_Recv( &buf[bufptr], RECV_BUF_SIZE, MPI_CHAR, orig, tag,
-		     MPI_COMM_WORLD, &status );
-    if( retv != 0 ) return FALSE;
-    MPI_Get_count( &status, MPI_CHAR, &n );
-    bufptr += n;
-
-    if( n == RECV_BUF_SIZE ) {
-      /* if not enough space, expand buffer */
-      if( bufsize - bufptr <= RECV_BUF_SIZE ) expand_buffer(RECV_BUF_SIZE);
-    }
-    else {
-      /* we have gotten everything */
-      break;
-    }
+  /* receive the size of the term */
+  retv = MPI_Recv( &bufstrlen, 1, MPI_INT, orig, tag,
+		   MPI_COMM_WORLD, &status );
+  if( retv != MPI_SUCCESS ) {
+    printf("BOOOOOOOM! retv == %d\n", retv);
+    return FALSE;
   }
 
-  if( bufsize - bufptr <= 3 ) expand_buffer(3);
-  /* NULL-terminate the string and add the ". " termination
-     required by the parser. */
-  buf[bufptr] = 0;
-  strcat( buf, ". " );
-  bufstrlen = bufptr + 2;
-  bufptr = 0;
+#if 1
+  printf("About to receive %d chars from %d\n", bufstrlen, orig);
+#endif
 
-  if( orig == MPI_ANY_SOURCE ) unify(t_orig, MkIntTerm(status.MPI_SOURCE));
-  if( tag == MPI_ANY_TAG ) unify(t_tag, MkIntTerm(status.MPI_TAG));
+  /* adjust the buffer */
+  if( bufsize < bufstrlen ) expand_buffer(bufstrlen-bufsize);
+
+  /* Only the first packet can be from MPI_ANY_SOURCE */
+  if( orig == MPI_ANY_SOURCE ) {
+    orig = status.MPI_SOURCE;
+    retv = unify(t_orig, MkIntTerm(orig));
+    if( retv == FALSE ) puts( "PROBLEM1" );
+  }
+
+  /* Only the first packet can be of MPI_ANY_TAG */
+  if( tag == MPI_ANY_TAG ) {
+    tag = status.MPI_TAG;
+    retv = unify(t_tag, MkIntTerm(status.MPI_TAG));
+    if( retv == FALSE ) puts( "PROBLEM2" );
+  }
+
+  /* Receive the message as a C string */
+  retv = MPI_Recv( &buf[bufptr], bufstrlen, MPI_CHAR, orig, tag,
+		   MPI_COMM_WORLD, &status );
+  if( retv != MPI_SUCCESS ) {
+    printf("BOOOOOOOM! retv == %d\n", retv);
+    return FALSE;
+  }
+
+#if 1
+  {
+    int aa;
+    MPI_Get_count( &status, MPI_CHAR, &aa );
+    printf("Received %d chars from %d\n", aa, orig);
+  }
+#endif
 
   /* parse received string into a Prolog term */
-  return unify(ARG1, mpi_parse());
+  bufptr = 0;
+  retv = unify(t_data, mpi_parse());
+#if 1
+  printf("mpi_receive: t_data == %d, retv == %d\n", t_data, retv);
+#endif
+
+  return retv;
 }
 
 
@@ -451,9 +598,10 @@ p_mpi_bcast3()           /* mpi_bcast( ?data, +root, +max_size ) */
 }
 
 
-/* This is the same as above, but for dynamic data size.
-   It is implemented as two broadcasts, the first being the size
-   and the second the actual data.
+/*
+  This is the same as above, but for dynamic data size.
+  It is implemented as two broadcasts, the first being the size
+  and the second the actual data.
 */
 static Int
 p_mpi_bcast2()           /* mpi_bcast( ?data, +root ) */
@@ -469,6 +617,7 @@ p_mpi_bcast2()           /* mpi_bcast( ?data, +root ) */
   }
   root = IntOfTerm( t_root );
 
+
   /*  If this is the root processor, then the first argument must
       be bound to the term to be sent. */
   if( root == rank ) {
@@ -478,27 +627,45 @@ p_mpi_bcast2()           /* mpi_bcast( ?data, +root ) */
     }
     bufptr = 0;
     /* Turn the term into its ASCII representation */
+puts("1");
     plwrite( t_data, mpi_putc, 5 );
     /* NULL-terminate the string and add the ". " termination
        required by the parser. */
+puts("1");
     buf[bufptr] = 0;
     strcat( buf, ". " );
     bufstrlen = bufptr + 2;
   }
+  /* Otherwise, it must a variable */
+  else {
+    if( !IsVarTerm(t_data) ) {
+      Error(INSTANTIATION_ERROR, t_data, "mpi_bcast");
+      return FALSE;
+    }
+  }
+
 
   /* Broadcast the data size */
   retv = MPI_Bcast( &bufstrlen, sizeof bufstrlen, MPI_INT, root, MPI_COMM_WORLD );
-  if( retv != 0 ) return FALSE;
+  if( retv != MPI_SUCCESS ) {
+    printf("PROBLEM: file %s, line %d\n", __FILE__, __LINE__);
+    return FALSE;
+  }
 
   /* adjust the buffer size, if necessary */
   if( bufstrlen > bufsize ) {
     printf("expanding by %d\n", (bufstrlen-bufsize) );
     expand_buffer( bufstrlen - bufsize );
   }
-
+  else {
+    printf("bufstrlen: %d, bufsize %d: not expanding\n",bufstrlen,bufsize);
+  }
   /* Broadcast the data */
   retv = MPI_Bcast( buf, bufstrlen, MPI_CHAR, root, MPI_COMM_WORLD );
-  if( retv != 0 ) return FALSE;
+  if( retv != MPI_SUCCESS ) {
+    printf("PROBLEM: file %s, line %d\n", __FILE__, __LINE__);
+    return FALSE;
+  }
 
   if( root == rank ) return TRUE;
   else {
@@ -571,13 +738,13 @@ InitMPI(void)
   }
 #endif  
 
-  InitCPred( "mpi_open", 3, p_mpi_open, /*SafePredFlag|SyncPredFlag*/ 0 );
-  InitCPred( "mpi_close", 0, p_mpi_close, SafePredFlag );
-  InitCPred( "mpi_send", 3, p_mpi_send, SafePredFlag );
-  InitCPred( "mpi_receive", 3, p_mpi_receive, SyncPredFlag );
-  InitCPred( "mpi_bcast", 3, p_mpi_bcast3, SyncPredFlag );
-  InitCPred( "mpi_bcast", 2, p_mpi_bcast2, SyncPredFlag );
-  InitCPred( "mpi_barrier", 0, p_mpi_barrier, 0 );
+  InitCPred( "mpi_open", 3, p_mpi_open, SafePredFlag|SyncPredFlag );
+  InitCPred( "mpi_close", 0, p_mpi_close, SyncPredFlag );
+  InitCPred( "mpi_send", 3, p_mpi_send, SafePredFlag|SyncPredFlag );
+  InitCPred( "mpi_receive", 3, p_mpi_receive, SafePredFlag|SyncPredFlag );
+  InitCPred( "mpi_bcast", 3, p_mpi_bcast3, SafePredFlag|SyncPredFlag );
+  InitCPred( "mpi_bcast", 2, p_mpi_bcast2, SafePredFlag|SyncPredFlag );
+  InitCPred( "mpi_barrier", 0, p_mpi_barrier, SyncPredFlag );
 }
 
 #endif /* HAVE_MPI */