diff --git a/compat/forkpty-hpux.c b/compat/forkpty-hpux.c
index 90452f8d..c72e096d 100644
--- a/compat/forkpty-hpux.c
+++ b/compat/forkpty-hpux.c
@@ -29,7 +29,7 @@
 pid_t
 forkpty(int *master, char *name, struct termios *tio, struct winsize *ws)
 {
-	int	slave;
+	int	slave = -1;
 	char   *path;
 	pid_t	pid;
 
diff --git a/compat/forkpty-sunos.c b/compat/forkpty-sunos.c
index 7b254d82..0015bf48 100644
--- a/compat/forkpty-sunos.c
+++ b/compat/forkpty-sunos.c
@@ -30,7 +30,7 @@
 pid_t
 forkpty(int *master, char *name, struct termios *tio, struct winsize *ws)
 {
-	int	slave;
+	int	slave = -1;
 	char   *path;
 	pid_t	pid;