diff --git a/ChangeLog b/ChangeLog
index 6755bf400f..d95a38a3ee 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,14 @@ Wed Mar 31 11:52:39 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 	* lib/delegate.rb (DelegateClass): define internal methods of the
 	  result class, but not metaclass of the caller.
 
+Wed Mar 31 11:17:16 2004  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* pack.c (pack_pack): raises RangeError if uv is out of UTF8 value
+	  range.  [ruby-dev:23281]
+
+	* io.c (rb_io_binmode): stdio buffer should be empty when calling
+	  IO#binmode.  [ruby-talk:96155]
+
 Tue Mar 30 20:25:34 2004  Tanaka Akira  <akr@m17n.org>
 
 	* time.c (search_time_t): limit guess range by mktime if it is
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index e62837891b..3bbc5fc8ea 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -528,6 +528,15 @@ bsock_do_not_rev_lookup_set(self, val)
     return val;
 }
 
+static void
+raise_socket_error(reason, error)
+    char *reason;
+    int error;
+{
+    if (error == EAI_SYSTEM) rb_sys_fail(reason);
+    rb_raise(rb_eSocket, "%s: %s", reason, gai_strerror(error));
+}
+
 static void
 make_ipaddr0(addr, buf, len)
     struct sockaddr *addr;
@@ -538,7 +547,7 @@ make_ipaddr0(addr, buf, len)
 
     error = getnameinfo(addr, SA_LEN(addr), buf, len, NULL, 0, NI_NUMERICHOST);
     if (error) {
-	rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));
+	raise_socket_error("getnameinfo", error);
     }
 }
 
@@ -680,7 +689,7 @@ sock_addrinfo(host, port, socktype, flags)
 	if (hostp && hostp[strlen(hostp)-1] == '\n') {
 	    rb_raise(rb_eSocket, "newline at the end of hostname");
 	}
-	rb_raise(rb_eSocket, "getaddrinfo: %s", gai_strerror(error));
+	raise_socket_error("getaddrinfo", error);
     }
 
 #if defined(__APPLE__) && defined(__MACH__)
@@ -744,14 +753,14 @@ ipaddr(sockaddr, norevlookup)
 	error = getnameinfo(sockaddr, SA_LEN(sockaddr), hbuf, sizeof(hbuf),
 			    NULL, 0, 0);
 	if (error) {
-	    rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));
+	    raise_socket_error("getnameinfo", error);
 	}
 	addr1 = rb_str_new2(hbuf);
     }
     error = getnameinfo(sockaddr, SA_LEN(sockaddr), hbuf, sizeof(hbuf),
 			pbuf, sizeof(pbuf), NI_NUMERICHOST | NI_NUMERICSERV);
     if (error) {
-	rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));
+	raise_socket_error("getnameinfo", error);
     }
     addr2 = rb_str_new2(hbuf);
     if (norevlookup) {
@@ -2210,7 +2219,7 @@ sock_s_getaddrinfo(argc, argv)
     }
     error = getaddrinfo(hptr, pptr, &hints, &res);
     if (error) {
-	rb_raise(rb_eSocket, "getaddrinfo: %s", gai_strerror(error));
+	raise_socket_error("getaddrinfo", error);
     }
 
     ret = make_addrinfo(res);
@@ -2347,11 +2356,11 @@ sock_s_getnameinfo(argc, argv)
 
   error_exit_addr:
     if (res) freeaddrinfo(res);
-    rb_raise(rb_eSocket, "getaddrinfo: %s", gai_strerror(error));
+    raise_socket_error("getaddrinfo", error);
 
   error_exit_name:
     if (res) freeaddrinfo(res);
-    rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));
+    raise_socket_error("getnameinfo", error);
 }
 
 static VALUE
diff --git a/io.c b/io.c
index 637dfeae3e..ef46499920 100644
--- a/io.c
+++ b/io.c
@@ -2133,6 +2133,9 @@ rb_io_binmode(io)
     OpenFile *fptr;
 
     GetOpenFile(io, fptr);
+    if ((fptr->mode & FMODE_BINMODE) && READ_DATA_BUFFERED(fptr->f)) {
+	rb_raise(rb_eIOError, "buffer already filled with text-mode content");
+    }
 #ifdef __human68k__
     if (fptr->f)
 	fmode(fptr->f, _IOBIN);
diff --git a/pack.c b/pack.c
index 9680b0fd7f..f011a1f2c4 100644
--- a/pack.c
+++ b/pack.c
@@ -866,8 +866,12 @@ pack_pack(ary, fmt)
 		int le;
 
 		from = NEXTFROM;
+		from = rb_to_int(from);
 		l = num2i32(from);
 		le = uv_to_utf8(buf, l);
+		if (TYPE(from) == T_BIGNUM) {
+		    rb_raise(rb_eRangeError, "pack(U): value out of range");
+		}
 		rb_str_buf_cat(res, (char*)buf, le);
 	    }
 	    break;
@@ -2024,7 +2028,7 @@ uv_to_utf8(buf, uv)
 	buf[5] = (uv&0x3f)|0x80;
 	return 6;
     }
-    rb_raise(rb_eArgError, "pack(U): value out of range");
+    rb_raise(rb_eRangeError, "pack(U): value out of range");
 }
 
 static const long utf8_limits[] = {