diff --git a/lib/linux/_open3.c b/lib/linux/_open3.c
index 8f103e7b..3072f9bf 100644
--- a/lib/linux/_open3.c
+++ b/lib/linux/_open3.c
@@ -27,7 +27,6 @@ int
 _open3 (char const *file_name, int flags, int mask)
 {
   int r = _sys_call3 (SYS_open, (long) file_name, (int) flags, (int) mask);
-  __ungetc_init ();
   if (r > 2)
     {
       __ungetc_clear (r);
diff --git a/lib/mes/fdgetc.c b/lib/mes/fdgetc.c
index 0370c24e..e5c63a75 100644
--- a/lib/mes/fdgetc.c
+++ b/lib/mes/fdgetc.c
@@ -31,6 +31,8 @@ int *__ungetc_buf;
 int
 __ungetc_p (int filedes)
 {
+  if (__ungetc_buf == 0)
+    __ungetc_init ();
   return __ungetc_buf[filedes] >= 0;
 }
 
@@ -49,19 +51,24 @@ __ungetc_init ()
 void
 __ungetc_clear (int filedes)
 {
+  if (__ungetc_buf == 0)
+    __ungetc_init ();
   __ungetc_buf[filedes] = -1;
 }
 
 void
 __ungetc_set (int filedes, int c)
 {
+  if (__ungetc_buf == 0)
+    __ungetc_init ();
   __ungetc_buf[filedes] = c;
 }
 
 int
 fdgetc (int fd)
 {
-  __ungetc_init ();
+  if (__ungetc_buf == 0)
+    __ungetc_init ();
 
   char c;
   int i = __ungetc_buf[fd];
diff --git a/lib/mes/fdungetc.c b/lib/mes/fdungetc.c
index 20ef9e87..2179aeb0 100644
--- a/lib/mes/fdungetc.c
+++ b/lib/mes/fdungetc.c
@@ -24,7 +24,6 @@
 int
 fdungetc (int c, int fd)
 {
-  __ungetc_init ();
   if (c == -1)
     return c;
   else if (__ungetc_p (fd))
diff --git a/lib/mes/mes_open.c b/lib/mes/mes_open.c
index 5ab184f5..13edc022 100644
--- a/lib/mes/mes_open.c
+++ b/lib/mes/mes_open.c
@@ -32,7 +32,6 @@ int __stderr = STDERR;
 int
 mes_open (char const *file_name, int flags, int mask)
 {
-  __ungetc_init ();
   int filedes = open (file_name, flags, mask);
   if (filedes > 2)
     __ungetc_clear (filedes);