diff --git a/unix/gtkcomm.c b/unix/gtkcomm.c
index 6100990e..b50b6d59 100644
--- a/unix/gtkcomm.c
+++ b/unix/gtkcomm.c
@@ -82,11 +82,11 @@ gboolean fd_input_func(GIOChannel *source, GIOCondition condition,
      * marker.
      */
     if (condition & G_IO_PRI)
-        select_result(sourcefd, 4);
+        select_result(sourcefd, SELECT_X);
     if (condition & (G_IO_IN | G_IO_HUP))
-        select_result(sourcefd, 1);
+        select_result(sourcefd, SELECT_R);
     if (condition & G_IO_OUT)
-        select_result(sourcefd, 2);
+        select_result(sourcefd, SELECT_W);
 
     return true;
 }
@@ -94,11 +94,11 @@ gboolean fd_input_func(GIOChannel *source, GIOCondition condition,
 void fd_input_func(gpointer data, gint sourcefd, GdkInputCondition condition)
 {
     if (condition & GDK_INPUT_EXCEPTION)
-        select_result(sourcefd, 4);
+        select_result(sourcefd, SELECT_X);
     if (condition & GDK_INPUT_READ)
-        select_result(sourcefd, 1);
+        select_result(sourcefd, SELECT_R);
     if (condition & GDK_INPUT_WRITE)
-        select_result(sourcefd, 2);
+        select_result(sourcefd, SELECT_W);
 }
 #endif
 
diff --git a/unix/unix.h b/unix/unix.h
index 1a74492a..684080f7 100644
--- a/unix/unix.h
+++ b/unix/unix.h
@@ -315,6 +315,7 @@ void uxsel_init(void);
 typedef void (*uxsel_callback_fn)(int fd, int event);
 void uxsel_set(int fd, int rwx, uxsel_callback_fn callback);
 void uxsel_del(int fd);
+enum { SELECT_R = 1, SELECT_W = 2, SELECT_X = 4 };
 void select_result(int fd, int event);
 int first_fd(int *state, int *rwx);
 int next_fd(int *state, int *rwx);
diff --git a/unix/uxagentc.c b/unix/uxagentc.c
index 42c1b373..097bdbb0 100644
--- a/unix/uxagentc.c
+++ b/unix/uxagentc.c
@@ -104,7 +104,7 @@ static void agent_select_result(int fd, int event)
 {
     agent_pending_query *conn;
 
-    assert(event == 1);		       /* not selecting for anything but R */
+    assert(event == SELECT_R);  /* not selecting for anything but R */
 
     conn = find234(agent_pending_queries, &fd, agent_connfind);
     if (!conn) {
@@ -203,7 +203,7 @@ agent_pending_query *agent_query(
 	agent_pending_queries = newtree234(agent_conncmp);
     add234(agent_pending_queries, conn);
 
-    uxsel_set(sock, 1, agent_select_result);
+    uxsel_set(sock, SELECT_R, agent_select_result);
     return conn;
 
     failure:
diff --git a/unix/uxfdsock.c b/unix/uxfdsock.c
index 54b29f6c..b6b43fa2 100644
--- a/unix/uxfdsock.c
+++ b/unix/uxfdsock.c
@@ -192,7 +192,7 @@ static int fdsocket_try_send(FdSocket *fds)
     if (bufchain_size(&fds->pending_output_data) == 0)
 	uxsel_del(fds->outfd);
     else
-	uxsel_set(fds->outfd, 2, fdsocket_select_result_output);
+	uxsel_set(fds->outfd, SELECT_W, fdsocket_select_result_output);
 
     return sent;
 }
@@ -245,7 +245,7 @@ static void fdsocket_set_frozen(Socket *s, bool is_frozen)
     if (is_frozen)
 	uxsel_del(fds->infd);
     else
-	uxsel_set(fds->infd, 1, fdsocket_select_result_input);
+	uxsel_set(fds->infd, SELECT_R, fdsocket_select_result_input);
 }
 
 static const char *fdsocket_socket_error(Socket *s)
@@ -349,7 +349,7 @@ Socket *make_fd_socket(int infd, int outfd, int inerrfd, Plug *plug)
         if (!fdsocket_by_infd)
             fdsocket_by_infd = newtree234(fdsocket_infd_cmp);
         add234(fdsocket_by_infd, fds);
-        uxsel_set(fds->infd, 1, fdsocket_select_result_input);
+        uxsel_set(fds->infd, SELECT_R, fdsocket_select_result_input);
     }
 
     if (fds->inerrfd >= 0) {
@@ -357,7 +357,7 @@ Socket *make_fd_socket(int infd, int outfd, int inerrfd, Plug *plug)
         if (!fdsocket_by_inerrfd)
             fdsocket_by_inerrfd = newtree234(fdsocket_inerrfd_cmp);
         add234(fdsocket_by_inerrfd, fds);
-        uxsel_set(fds->inerrfd, 1, fdsocket_select_result_input_error);
+        uxsel_set(fds->inerrfd, SELECT_R, fdsocket_select_result_input_error);
     }
 
     return &fds->sock;
diff --git a/unix/uxnet.c b/unix/uxnet.c
index b60b933a..b8c9c505 100644
--- a/unix/uxnet.c
+++ b/unix/uxnet.c
@@ -1283,7 +1283,7 @@ static void net_select_result(int fd, int event)
     noise_ultralight(NOISE_SOURCE_IOID, fd);
 
     switch (event) {
-      case 4:			       /* exceptional */
+      case SELECT_X:                   /* exceptional */
 	if (!s->oobinline) {
 	    /*
 	     * On a non-oobinline socket, this indicates that we
@@ -1320,7 +1320,7 @@ static void net_select_result(int fd, int event)
 	 */
 	s->oobpending = true;
         break;
-      case 1: 			       /* readable; also acceptance */
+      case SELECT_R:                   /* readable; also acceptance */
 	if (s->listener) {
 	    /*
 	     * On a listening socket, the readability event means a
@@ -1400,7 +1400,7 @@ static void net_select_result(int fd, int event)
 	    plug_receive(s->plug, atmark ? 0 : 1, buf, ret);
 	}
 	break;
-      case 2:			       /* writable */
+      case SELECT_W:                   /* writable */
 	if (!s->connected) {
 	    /*
 	     * select() reports a socket as _writable_ when an
@@ -1559,14 +1559,14 @@ static void uxsel_tell(NetSocket *s)
     int rwx = 0;
     if (!s->pending_error) {
         if (s->listener) {
-            rwx |= 1;                  /* read == accept */
+            rwx |= SELECT_R;           /* read == accept */
         } else {
             if (!s->connected)
-                rwx |= 2;              /* write == connect */
+                rwx |= SELECT_W;       /* write == connect */
             if (s->connected && !s->frozen && !s->incomingeof)
-                rwx |= 1 | 4;          /* read, except */
+                rwx |= SELECT_R | SELECT_X;
             if (bufchain_size(&s->output_data))
-                rwx |= 2;              /* write */
+                rwx |= SELECT_W;
         }
     }
     uxsel_set(s->s, rwx, net_select_result);
diff --git a/unix/uxpgnt.c b/unix/uxpgnt.c
index d7fc90d0..5a1f6a51 100644
--- a/unix/uxpgnt.c
+++ b/unix/uxpgnt.c
@@ -958,11 +958,11 @@ void run_agent(void)
              * past the urgent marker.
              */
 	    if (FD_ISSET(fd, &xset))
-		select_result(fd, 4);
+		select_result(fd, SELECT_X);
 	    if (FD_ISSET(fd, &rset))
-		select_result(fd, 1);
+		select_result(fd, SELECT_R);
 	    if (FD_ISSET(fd, &wset))
-		select_result(fd, 2);
+		select_result(fd, SELECT_W);
 	}
 
         if (signalpipe[0] >= 0 && FD_ISSET(signalpipe[0], &rset)) {
diff --git a/unix/uxplink.c b/unix/uxplink.c
index ed4cd91e..ee7b6853 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -974,11 +974,11 @@ int main(int argc, char **argv)
              * past the urgent marker.
              */
 	    if (FD_ISSET(fd, &xset))
-		select_result(fd, 4);
+		select_result(fd, SELECT_X);
 	    if (FD_ISSET(fd, &rset))
-		select_result(fd, 1);
+		select_result(fd, SELECT_R);
 	    if (FD_ISSET(fd, &wset))
-		select_result(fd, 2);
+		select_result(fd, SELECT_W);
 	}
 
 	if (FD_ISSET(signalpipe[0], &rset)) {
diff --git a/unix/uxpty.c b/unix/uxpty.c
index 5d73fe9c..b499fb21 100644
--- a/unix/uxpty.c
+++ b/unix/uxpty.c
@@ -629,7 +629,7 @@ static void pty_real_select_result(Pty *pty, int fd, int event, int status)
                 finished = true;
 	}
     } else {
-	if (event == 1) {
+	if (event == SELECT_R) {
             bool is_stdout = (fd == pty->master_o);
 
 	    ret = read(fd, buf, sizeof(buf));
@@ -679,7 +679,7 @@ static void pty_real_select_result(Pty *pty, int fd, int event, int status)
 	    } else if (ret > 0) {
 		seat_output(pty->seat, !is_stdout, buf, ret);
 	    }
-	} else if (event == 2) {
+	} else if (event == SELECT_W) {
             /*
              * Attempt to send data down the pty.
              */
@@ -781,10 +781,10 @@ static void pty_uxsel_setup_fd(Pty *pty, int fd)
 
     /* read from standard output and standard error pipes */
     if (pty->master_o == fd || pty->master_e == fd)
-        rwx |= 1;
+        rwx |= SELECT_R;
     /* write to standard input pipe if we have any data */
     if (pty->master_i == fd && bufchain_size(&pty->output_data))
-        rwx |= 2;
+        rwx |= SELECT_W;
 
     uxsel_set(fd, rwx, pty_select_result);
 }
@@ -794,9 +794,9 @@ static void pty_uxsel_setup(Pty *pty)
     /*
      * We potentially have three separate fds here, but on the other
      * hand, some of them might be the same (if they're a pty master).
-     * So we can't just call uxsel_set(master_o, 1) and then
-     * uxsel_set(master_i, 2), without the latter potentially undoing
-     * the work of the former if master_o == master_i.
+     * So we can't just call uxsel_set(master_o, SELECT_R) and then
+     * uxsel_set(master_i, SELECT_W), without the latter potentially
+     * undoing the work of the former if master_o == master_i.
      *
      * Instead, here we call a single uxsel on each one of these fds
      * (if it exists at all), and for each one, check it against all
@@ -811,7 +811,7 @@ static void pty_uxsel_setup(Pty *pty)
      * backend instances, but it's simplest just to call it every
      * time; uxsel won't mind.
      */
-    uxsel_set(pty_signal_pipe[0], 1, pty_select_result);
+    uxsel_set(pty_signal_pipe[0], SELECT_R, pty_select_result);
 }
 
 static void copy_ttymodes_into_termios(
diff --git a/unix/uxserver.c b/unix/uxserver.c
index 1771c272..206cc1d4 100644
--- a/unix/uxserver.c
+++ b/unix/uxserver.c
@@ -639,11 +639,11 @@ int main(int argc, char **argv)
              * past the urgent marker.
              */
 	    if (FD_ISSET(fd, &xset))
-		select_result(fd, 4);
+		select_result(fd, SELECT_X);
 	    if (FD_ISSET(fd, &rset))
-		select_result(fd, 1);
+		select_result(fd, SELECT_R);
 	    if (FD_ISSET(fd, &wset))
-		select_result(fd, 2);
+		select_result(fd, SELECT_W);
 	}
 
         run_toplevel_callbacks();
diff --git a/unix/uxsftp.c b/unix/uxsftp.c
index 1c48e0d5..3152f85e 100644
--- a/unix/uxsftp.c
+++ b/unix/uxsftp.c
@@ -543,11 +543,11 @@ static int ssh_sftp_do_select(bool include_stdin, bool no_fds_ok)
 	 * past the urgent marker.
 	 */
 	if (FD_ISSET(fd, &xset))
-	    select_result(fd, 4);
+	    select_result(fd, SELECT_X);
 	if (FD_ISSET(fd, &rset))
-	    select_result(fd, 1);
+	    select_result(fd, SELECT_R);
 	if (FD_ISSET(fd, &wset))
-	    select_result(fd, 2);
+	    select_result(fd, SELECT_W);
     }
 
     sfree(fdlist);