* ext/etc/etc.c: add new functions: setpwent, getpwent, endpwent,

  setgrent, getgrent, endgrent.

* ext/socket/socket.c (sock_s_gethostbyname): do not reverse lookup.

* Makefile.in: copy lex.c from $(srcdir) if it's not the current
  directory.  [ruby-dev:21437]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

7 files changed, 237 insertions, 231 deletions

diff --git a/ChangeLog b/ChangeLog
index f13ab7c4e9..df03ae4c6d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,13 @@ Wed Oct  1 20:36:49 2003  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* MANIFEST: add wince/mkconfig_wce.rb.
 
+Wed Oct  1 17:22:33 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* ext/etc/etc.c: add new functions: setpwent, getpwent, endpwent,
+	  setgrent, getgrent, endgrent.
+
+	* ext/socket/socket.c (sock_s_gethostbyname): do not reverse lookup.
+
 Wed Oct  1 17:01:30 2003  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* eval.c (rb_load): Object scope had priority over required file
@@ -32,6 +39,11 @@ Wed Oct 01 08:02:52 2003  Takaaki Uematsu <uema2x@jcom.home.ne.jp>
 
 	* wince/time_wce.c (time): add zero check.
 
+Tue Sep 30 16:11:05 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* Makefile.in: copy lex.c from $(srcdir) if it's not the current
+	  directory.  [ruby-dev:21437]
+
 Tue Sep 30 11:29:23 2003  Tanaka Akira  <akr@m17n.org>
 
 	* process.c (pst_inspect): describe stopped process "stopped".
diff --git a/Makefile.in b/Makefile.in
index f6a3cb6609..13de20321a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -218,7 +218,11 @@ $(srcdir)/configure: $(srcdir)/configure.in
 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
 
 lex.c: keywords
-	gperf -p -j1 -i 1 -g -o -t -N rb_reserved_word -k1,3,$$ $(srcdir)/keywords > lex.c
+	if test "$(srcdir)" = "."; then \
+	  gperf -p -j1 -i 1 -g -o -t -N rb_reserved_word -k1,3,$$ $> > $@; \
+	else \
+	  cp $(srcdir)/lex.c .; \
+	fi
 
 .y.c:
 	$(YACC) $<
diff --git a/eval.c b/eval.c
index d8162916ba..622bbeff65 100644
--- a/eval.c
+++ b/eval.c
@@ -9752,7 +9752,7 @@ static VALUE
 rb_thread_raise(argc, argv, th)
     int argc;
     VALUE *argv;
-    rb_thread_t th;
+    volatile rb_thread_t th;
 {
     if (rb_thread_dead(th)) return Qnil;
     if (curr_thread == th) {
@@ -9924,7 +9924,7 @@ rb_callcc(self)
     VALUE self;
 {
     volatile VALUE cont;
-    rb_thread_t th;
+    volatile rb_thread_t th;
     struct tag *tag;
     struct RVarmap *vars;
 
diff --git a/ext/etc/etc.c b/ext/etc/etc.c
index 51668c400f..3d4052e27b 100644
--- a/ext/etc/etc.c
+++ b/ext/etc/etc.c
@@ -175,6 +175,40 @@ etc_passwd(obj)
     return Qnil;
 }
 
+static VALUE
+etc_setpwent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETPWENT
+    setpwent();
+#endif
+    return Qnil;
+}
+
+static VALUE
+etc_endpwent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETPWENT
+    endpwent();
+#endif
+    return Qnil;
+}
+
+static VALUE
+etc_getpwent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETPWENT
+    struct passwd *pw;
+
+    if (pw = getpwent()) {
+	return setup_passwd(pw);
+    }
+#endif
+    return Qnil;
+}
+
 #ifdef HAVE_GETGRENT
 static VALUE
 setup_group(grp)
@@ -246,11 +280,11 @@ group_iterate()
 {
     struct group *pw;
 
-    setpwent();
+    setgrent();
     while (pw = getgrent()) {
 	rb_yield(setup_group(pw));
     }
-    endpwent();
+    endgrent();
     return Qnil;
 }
 #endif
@@ -277,6 +311,40 @@ etc_group(obj)
     return Qnil;
 }
 
+static VALUE
+etc_setgrent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETGRENT
+    setgrent();
+#endif
+    return Qnil;
+}
+
+static VALUE
+etc_endgrent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETGRENT
+    endgrent();
+#endif
+    return Qnil;
+}
+
+static VALUE
+etc_getgrent(obj)
+    VALUE obj;
+{
+#ifdef HAVE_GETGRENT
+    struct group *gr;
+
+    if (gr = getgrent()) {
+	return setup_passwd(gr);
+    }
+#endif
+    return Qnil;
+}
+
 static VALUE mEtc;
 
 void
@@ -288,11 +356,17 @@ Init_etc()
 
     rb_define_module_function(mEtc, "getpwuid", etc_getpwuid, -1);
     rb_define_module_function(mEtc, "getpwnam", etc_getpwnam, 1);
+    rb_define_module_function(mEtc, "setpwent", etc_setpwent, 0);
+    rb_define_module_function(mEtc, "endpwent", etc_endpwent, 0);
+    rb_define_module_function(mEtc, "getpwent", etc_getpwent, 0);
     rb_define_module_function(mEtc, "passwd", etc_passwd, 0);
 
     rb_define_module_function(mEtc, "getgrgid", etc_getgrgid, 1);
     rb_define_module_function(mEtc, "getgrnam", etc_getgrnam, 1);
     rb_define_module_function(mEtc, "group", etc_group, 0);
+    rb_define_module_function(mEtc, "setgrent", etc_setgrent, 0);
+    rb_define_module_function(mEtc, "endgrent", etc_endgrent, 0);
+    rb_define_module_function(mEtc, "getgrent", etc_g,etgrent, 0);
 
     sPasswd =  rb_struct_define("Passwd",
 				"name", "passwd", "uid", "gid",
diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index e888b2a197..234f373170 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -385,6 +385,7 @@ have_header("sys/uio.h")
 
 if have_func(test_func)
   have_func("hsterror")
+  have_func("getipnodebyname") or have_func("gethostbyname2")
   unless have_func("gethostname")
     have_func("uname")
   end
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index ca2528f549..ca7bdc50c2 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -492,7 +492,7 @@ bsock_do_not_rev_lookup_set(self, val)
 }
 
 static void
-mkipaddr0(addr, buf, len)
+make_ipaddr0(addr, buf, len)
     struct sockaddr *addr;
     char *buf;
     size_t len;
@@ -506,17 +506,17 @@ mkipaddr0(addr, buf, len)
 }
 
 static VALUE
-mkipaddr(addr)
+make_ipaddr(addr)
     struct sockaddr *addr;
 {
     char buf[1024];
 
-    mkipaddr0(addr, buf, sizeof(buf));
+    make_ipaddr0(addr, buf, sizeof(buf));
     return rb_str_new2(buf);
 }
 
 static void
-mkinetaddr(host, buf, len)
+make_inetaddr(host, buf, len)
     long host;
     char *buf;
     size_t len;
@@ -527,7 +527,7 @@ mkinetaddr(host, buf, len)
     sin.sin_family = AF_INET;
     SET_SIN_LEN(&sin, sizeof(sin));
     sin.sin_addr.s_addr = host;
-    mkipaddr0((struct sockaddr*)&sin, buf, len);
+    make_ipaddr0((struct sockaddr*)&sin, buf, len);
 }
 
 static int
@@ -546,24 +546,20 @@ str_isnumber(p)
        return 0;
 }
 
-static struct addrinfo*
-sock_addrinfo(host, port, socktype, flags)
-    VALUE host, port;
-    int socktype, flags;
+static char *
+host_str(host, hbuf, len)
+    VALUE host;
+    char *hbuf;
+    size_t len;
 {
-    struct addrinfo hints, *hintsp, *res;
-    char *hostp, *portp;
-    int error;
-    char hbuf[1024], pbuf[32];
-
     if (NIL_P(host)) {
-	hostp = NULL;
+	return NULL;
     }
     else if (rb_obj_is_kind_of(host, rb_cInteger)) {
 	long i = NUM2LONG(host);
 
-	mkinetaddr(htonl(i), hbuf, sizeof(hbuf));
-	hostp = hbuf;
+	make_inetaddr(htonl(i), hbuf, len);
+	return hbuf;
     }
     else {
 	char *name;
@@ -571,30 +567,66 @@ sock_addrinfo(host, port, socktype, flags)
 	SafeStringValue(host);
 	name = RSTRING(host)->ptr;
 	if (!name || *name == 0 || (name[0] == '<' && strcmp(name, "<any>") == 0)) {
-	    mkinetaddr(INADDR_ANY, hbuf, sizeof(hbuf));
+	    make_inetaddr(INADDR_ANY, hbuf, len);
 	}
 	else if (name[0] == '<' && strcmp(name, "<broadcast>") == 0) {
-	    mkinetaddr(INADDR_BROADCAST, hbuf, sizeof(hbuf));
+	    make_inetaddr(INADDR_BROADCAST, hbuf, len);
 	}
-	else if (strlen(name) >= sizeof(hbuf)) {
+	else if (strlen(name) >= len) {
 	    rb_raise(rb_eArgError, "hostname too long (%d)", strlen(name));
 	}
 	else {
 	    strcpy(hbuf, name);
 	}
-	hostp = hbuf;
+	return hbuf;
     }
+}
+
+static char *
+port_str(port, pbuf, len)
+    VALUE port;
+    char *pbuf;
+    size_t len;
+{
     if (NIL_P(port)) {
-	portp = 0;
+	return 0;
     }
     else if (FIXNUM_P(port)) {
-	snprintf(pbuf, sizeof(pbuf), "%d", FIX2INT(port));
-	portp = pbuf;
+	snprintf(pbuf, len, "%d", FIX2INT(port));
+	return pbuf;
     }
     else {
+	char *serv;
+
 	SafeStringValue(port);
-	portp = RSTRING(port)->ptr;
+	serv = RSTRING(port)->ptr;
+	if (strlen(serv) >= len) {
+	    rb_raise(rb_eArgError, "service name too long (%d)", strlen(serv));
+	}
+	strcpy(pbuf, serv);
+	return pbuf;
     }
+}
+
+#ifndef NI_MAXHOST
+# define 1025
+#endif
+#ifndef NI_MAXSERV
+# define 32
+#endif
+
+static struct addrinfo*
+sock_addrinfo(host, port, socktype, flags)
+    VALUE host, port;
+    int socktype, flags;
+{
+    struct addrinfo hints, *hintsp, *res;
+    char *hostp, *portp;
+    int error;
+    char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
+
+    hostp = host_str(host, hbuf, sizeof(hbuf));
+    portp = port_str(port, pbuf, sizeof(pbuf));
 
     if (socktype == 0 && flags == 0 && str_isnumber(portp)) {
        socktype = SOCK_DGRAM;
@@ -617,18 +649,6 @@ sock_addrinfo(host, port, socktype, flags)
     return res;
 }
 
-static void
-setipaddr(name, addr)
-    VALUE name;
-    struct sockaddr_storage *addr;
-{
-    struct addrinfo *res = sock_addrinfo(name, Qnil, SOCK_STREAM, 0);
-
-    /* just take the first one */
-    memcpy(addr, res->ai_addr, res->ai_addrlen);
-    freeaddrinfo(res);
-}
-
 static VALUE
 ipaddr(sockaddr)
     struct sockaddr *sockaddr;
@@ -704,17 +724,6 @@ ruby_socket(domain, type, proto)
 }
 
 static void
-thread_read_select(fd)
-    int fd;
-{
-    fd_set fds;
-
-    FD_ZERO(&fds);
-    FD_SET(fd, &fds);
-    rb_thread_select(fd+1, &fds, 0, 0, 0);
-}
-
-static void
 thread_write_select(fd)
     int fd;
 {
@@ -845,46 +854,6 @@ ruby_connect(fd, sockaddr, len, socks)
     }
 }
 
-static void
-load_addr_info(h, serv, type, res)
-    VALUE h, serv;
-    int type;
-    struct addrinfo **res;
-{
-    char *host;
-    char pbuf[1024], *portp;
-    struct addrinfo hints;
-    int error;
-
-    if (!NIL_P(h)) {
-	SafeStringValue(h);
-	host = RSTRING(h)->ptr;
-    }
-    else {
-	host = NULL;
-    }
-    if (FIXNUM_P(serv)) {
-	snprintf(pbuf, sizeof(pbuf), "%u", FIX2UINT(serv));
-	portp = pbuf;
-    }
-    else {
-	SafeStringValue(serv);
-	if (RSTRING(serv)->len >= sizeof(pbuf))
-	    rb_raise(rb_eArgError, "servicename too long (%ld)", RSTRING(serv)->len);
-	strcpy(pbuf, RSTRING(serv)->ptr);
-	portp = pbuf;
-    }
-    MEMZERO(&hints, struct addrinfo, 1);
-    hints.ai_family = PF_UNSPEC;
-    if (type == INET_SERVER) {
-	hints.ai_flags = AI_PASSIVE;
-    }
-    error = getaddrinfo(host, portp, &hints, res);
-    if (error) {
-	rb_raise(rb_eSocket, "getaddrinfo: %s", gai_strerror(error));
-    }
-}
-
 struct inetsock_arg
 {
     VALUE sock;
@@ -1052,112 +1021,61 @@ socks_s_close(sock)
 #endif
 #endif
 
-/*
- * NOTE: using gethostbyname() against AF_INET6 is a bad idea, as it
- * does not initialize sin_flowinfo nor sin_scope_id properly.
- */
-
-struct hostent*
-sock_hostbyname(host)
-    VALUE host;
-{
-    struct sockaddr_storage addr;
-    struct hostent *h;
-
-    rb_secure(3);
-    setipaddr(host, &addr);
-    switch (addr.ss_family) {
-      case AF_INET:
-      {
-	struct sockaddr_in *sin;
-	sin = (struct sockaddr_in*)&addr;
-	h = gethostbyaddr((char*)&sin->sin_addr,
-			  sizeof(sin->sin_addr),
-			  sin->sin_family);
-	break;
-      }
-#ifdef INET6
-      case AF_INET6:
-      {
-	struct sockaddr_in6 *sin6;
-	sin6 = (struct sockaddr_in6*)&addr;
-	h = gethostbyaddr((char*)&sin6->sin6_addr,
-			  sizeof(sin6->sin6_addr),
-			  sin6->sin6_family);
-	break;
-      }
-#endif
-      default:
-	h = NULL;
-	break;
-    }
-
-    if (h == NULL) {
-#ifdef HAVE_HSTERROR
-	extern int h_errno;
-	rb_raise(rb_eSocket, "%s", (char*)hsterror(h_errno));
-#else
-	rb_raise(rb_eSocket, "host not found");
-#endif
-    }
-    return h;
-}
-
 static VALUE
-tcp_s_gethostbyname(obj, host)
-    VALUE obj, host;
+make_hostent(addr, ipaddr)
+    struct addrinfo *addr;
+    VALUE (*ipaddr) _((struct sockaddr*, size_t));
 {
-    struct hostent *h = sock_hostbyname(host);
+    struct addrinfo *ai;
+    struct hostent *h;
     VALUE ary, names;
     char **pch;
 
     ary = rb_ary_new();
-    rb_ary_push(ary, rb_str_new2(h->h_name));
+    rb_ary_push(ary, rb_str_new2(addr->ai_canonname));
     names = rb_ary_new();
     rb_ary_push(ary, names);
+#if defined(HAVE_GETIPNODEBYNAME)
+    {
+	int error;
+
+	h = getipnodebyname(addr->ai_canonname, addr->ai_family, AI_ALL, &error);
+    }
+#elif defined(HAVE_GETHOSTBYNAME2)
+    h = gethostbyname2(addr->ai_canonname, addr->ai_family);
+#else
+    h = gethostbyname(addr->ai_canonname);
+#endif
     for (pch = h->h_aliases; *pch; pch++) {
 	rb_ary_push(names, rb_str_new2(*pch));
     }
-    rb_ary_push(ary, INT2NUM(h->h_addrtype));
-#ifdef h_addr
-    for (pch = h->h_addr_list; *pch; pch++) {
-	switch (h->h_length) {
-	  case 4: /* AF_INET */ {
-	    struct sockaddr_in sin;
-
-	    MEMZERO(&sin, struct sockaddr_in, 1);
-	    sin.sin_family = AF_INET;
-	    SET_SIN_LEN(&sin, sizeof(sin));
-	    memcpy((char*)&sin.sin_addr, *pch, h->h_length);
-	    rb_ary_push(ary, mkipaddr((struct sockaddr*)&sin));
-	    break;
-	  }
-#ifdef INET6
-	  case 8: /* AF_INET6 */ {
-	    struct sockaddr_in6 sin6;
-
-	    MEMZERO(&sin6, struct sockaddr_in6, 1);
-	    sin6.sin6_family = AF_INET6;
-#ifdef SIN6_LEN
-	    sin6.sin6_len = sizeof(sin6);
+#if defined(HAVE_GETIPNODEBYNAME)
+    freehostent(h);
 #endif
-	    memcpy((char*)&sin6.sin6_addr, *pch, h->h_length);
-	    rb_ary_push(ary, mkipaddr((struct sockaddr*)&sin6));
-	    break;
-	  }
-#endif
-	  default:
-	    break;
-	}
+    rb_ary_push(ary, INT2NUM(addr->ai_family));
+    for (ai = addr; ai; ai = ai->ai_next) {
+	rb_ary_push(ary, (*ipaddr)(ai->ai_addr, ai->ai_addrlen));
     }
-#else
-    memcpy((char*)&addr.sin_addr, h->h_addr, h->h_length);
-    rb_ary_push(ary, mkipaddr((struct sockaddr*)&addr));
-#endif
 
     return ary;
 }
 
+VALUE
+tcp_sockaddr(addr, len)
+    struct sockaddr *addr;
+    size_t len;
+{
+    return make_ipaddr(addr);
+}
+
+static VALUE
+tcp_s_gethostbyname(obj, host)
+    VALUE obj, host;
+{
+    rb_secure(3);
+    return make_hostent(sock_addrinfo(host, Qnil, SOCK_STREAM, AI_CANONNAME), tcp_sockaddr);
+}
+
 static VALUE
 tcp_svr_init(argc, argv, sock)
     int argc;
@@ -1347,9 +1265,13 @@ ip_s_getaddress(obj, host)
     VALUE obj, host;
 {
     struct sockaddr_storage addr;
+    struct addrinfo *res = sock_addrinfo(host, Qnil, SOCK_STREAM, 0);
+
+    /* just take the first one */
+    memcpy(&addr, res->ai_addr, res->ai_addrlen);
+    freeaddrinfo(res);
 
-    setipaddr(host, &addr);
-    return mkipaddr((struct sockaddr*)&addr);
+    return make_ipaddr((struct sockaddr*)&addr);
 }
 
 static VALUE
@@ -1500,13 +1422,6 @@ unix_path(sock)
 }
 
 static VALUE
-unix_svr_s_open(klass, path)
-    VALUE klass, path;
-{
-    return init_unixsock(rb_obj_alloc(klass), path, 1);
-}
-
-static VALUE
 unix_svr_init(sock, path)
     VALUE sock, path;
 {
@@ -2023,41 +1938,7 @@ sock_gethostname(obj)
 #endif
 
 static VALUE
-sock_mkhostent(h)
-    struct hostent *h;
-{
-    char **pch;
-    VALUE ary, names;
-
-    if (h == NULL) {
-#ifdef HAVE_HSTRERROR
-	extern int h_errno;
-	rb_raise(rb_eSocket, "%s", (char*)hstrerror(h_errno));
-#else
-	rb_raise(rb_eSocket, "host not found");
-#endif
-    }
-    ary = rb_ary_new();
-    rb_ary_push(ary, rb_str_new2(h->h_name));
-    names = rb_ary_new();
-    rb_ary_push(ary, names);
-    for (pch = h->h_aliases; *pch; pch++) {
-	rb_ary_push(names, rb_str_new2(*pch));
-    }
-    rb_ary_push(ary, INT2NUM(h->h_addrtype));
-#ifdef h_addr
-    for (pch = h->h_addr_list; *pch; pch++) {
-	rb_ary_push(ary, rb_str_new(*pch, h->h_length));
-    }
-#else
-    rb_ary_push(ary, rb_str_new(h->h_addr, h->h_length));
-#endif
-
-    return ary;
-}
-
-static VALUE
-mkaddrinfo(res0)
+make_addrinfo(res0)
     struct addrinfo *res0;
 {
     VALUE base, ary;
@@ -2077,11 +1958,20 @@ mkaddrinfo(res0)
     return base;
 }
 
+VALUE
+sock_sockaddr(addr, len)
+    struct sockaddr *addr;
+    size_t len;
+{
+    return rb_str_new((char*)addr, len);
+}
+
 static VALUE
 sock_s_gethostbyname(obj, host)
     VALUE obj, host;
 {
-    return sock_mkhostent(sock_hostbyname(host));
+    rb_secure(3);
+    return make_hostent(sock_addrinfo(host, Qnil, SOCK_STREAM, AI_CANONNAME), sock_sockaddr);
 }
 
 static VALUE
@@ -2092,6 +1982,8 @@ sock_s_gethostbyaddr(argc, argv)
     VALUE addr, type;
     struct hostent *h;
     struct sockaddr *sa;
+    char **pch;
+    VALUE ary, names;
     int t = AF_INET;
 
     rb_scan_args(argc, argv, "11", &addr, &type);
@@ -2105,8 +1997,31 @@ sock_s_gethostbyaddr(argc, argv)
     }
 #endif
     h = gethostbyaddr(RSTRING(addr)->ptr, RSTRING(addr)->len, t);
+    if (h == NULL) {
+#ifdef HAVE_HSTRERROR
+	extern int h_errno;
+	rb_raise(rb_eSocket, "%s", (char*)hstrerror(h_errno));
+#else
+	rb_raise(rb_eSocket, "host not found");
+#endif
+    }
+    ary = rb_ary_new();
+    rb_ary_push(ary, rb_str_new2(h->h_name));
+    names = rb_ary_new();
+    rb_ary_push(ary, names);
+    for (pch = h->h_aliases; *pch; pch++) {
+	rb_ary_push(names, rb_str_new2(*pch));
+    }
+    rb_ary_push(ary, INT2NUM(h->h_addrtype));
+#ifdef h_addr
+    for (pch = h->h_addr_list; *pch; pch++) {
+	rb_ary_push(ary, rb_str_new(*pch, h->h_length));
+    }
+#else
+    rb_ary_push(ary, rb_str_new(h->h_addr, h->h_length));
+#endif
 
-    return sock_mkhostent(h);
+    return ary;
 }
 
 static VALUE
@@ -2206,7 +2121,7 @@ sock_s_getaddrinfo(argc, argv)
 	rb_raise(rb_eSocket, "getaddrinfo: %s", gai_strerror(error));
     }
 
-    ret = mkaddrinfo(res);
+    ret = make_addrinfo(res);
     freeaddrinfo(res);
     return ret;
 }
@@ -2369,7 +2284,7 @@ sock_s_unpack_sockaddr_in(self, addr)
     VALUE host;
 
     sockaddr = (struct sockaddr_in*)StringValuePtr(addr);
-    host = mkipaddr((struct sockaddr*)sockaddr);
+    host = make_ipaddr((struct sockaddr*)sockaddr);
     OBJ_INFECT(host, addr);
     return rb_assoc_new(INT2NUM(ntohs(sockaddr->sin_port)), host);
 }
diff --git a/intern.h b/intern.h
index 93e6bb8d11..dacd985b74 100644
--- a/intern.h
+++ b/intern.h
@@ -374,7 +374,7 @@ void posix_signal _((int, RETSIGTYPE (*)(int)));
 #endif
 void rb_trap_exit _((void));
 void rb_trap_exec _((void));
-char *ruby_signal_name _((int));
+const char *ruby_signal_name _((int));
 /* sprintf.c */
 VALUE rb_f_sprintf _((int, VALUE*));
 /* string.c */