diff --git a/c/external.c b/c/external.c
index acad561..bd3eabd 100644
--- a/c/external.c
+++ b/c/external.c
@@ -301,7 +301,7 @@ s48_call_scheme(s48_value proc, long nargs, ...)
 
   /* It would be nice to push a list of the arguments, but we have no way
      of preserving them across a cons. */
-  if (nargs < 0 || 10 < nargs) {  /* DO NOT INCREASE THIS NUMBER */
+  if (nargs < 0 || 12 < nargs) {  /* DO NOT INCREASE THIS NUMBER */
     s48_value sch_nargs = s48_enter_integer(nargs);  /* `proc' is protected */
     s48_raise_scheme_exception(S48_EXCEPTION_TOO_MANY_ARGUMENTS_IN_CALLBACK,
 			       2, proc, sch_nargs);
@@ -585,7 +585,7 @@ s48_stob_set(s48_value thing, int type, long offset, s48_value value)
 }
 
 char
-s48_byte_ref(s48_value thing, int type, long offset)
+s48_stob_byte_ref(s48_value thing, int type, long offset)
 {
   long length;
 
@@ -605,7 +605,7 @@ s48_byte_ref(s48_value thing, int type, long offset)
 }
 
 void
-s48_byte_set(s48_value thing, int type, long offset, char value)
+s48_stob_byte_set(s48_value thing, int type, long offset, char value)
 {
   long length;
 
@@ -894,9 +894,15 @@ s48_extract_byte_vector(s48_value bvec)
 }
 
 s48_value
-s48_make_byte_vector(int length)
+s48_make_byte_vector(int length, int init)
 {
-    return s48_allocate_stob(S48_STOBTYPE_BYTE_VECTOR, length);
+  int i;
+  s48_value obj = s48_allocate_stob(S48_STOBTYPE_BYTE_VECTOR, length);
+  
+  for (i = 0; i < length; i++)
+    S48_BYTE_VECTOR_SET(obj, i, init);
+  
+  return obj;
 }
 
 s48_value
diff --git a/c/scheme48.h.in b/c/scheme48.h.in
index 560786f..f811667 100644
--- a/c/scheme48.h.in
+++ b/c/scheme48.h.in
@@ -43,7 +43,7 @@ extern s48_value	s48_make_string(int, char);
 extern s48_value	s48_make_vector(int, s48_value);
 extern s48_value	s48_enter_byte_vector(char *, int);
 extern char *		s48_extract_byte_vector(s48_value);
-extern s48_value	s48_make_byte_vector(int);
+extern s48_value	s48_make_byte_vector(int, int);
 extern s48_value	s48_make_record(s48_value);
 extern s48_value	s48_make_weak_pointer(s48_value);
 extern void		s48_check_record_type(s48_value, s48_value);
@@ -60,7 +60,7 @@ extern s48_value	s48_call_scheme(s48_value proc, long nargs, ...);
 
 #define S48_EXPORT_FUNCTION(p) (s48_define_exported_binding(#p, s48_enter_pointer(p)))
 
-#define S48_MAKE_VALUE(type) (s48_make_byte_vector(sizeof(type)))
+#define S48_MAKE_VALUE(type) (s48_make_byte_vector(sizeof(type),0))
 extern void *		s48_value_pointer(s48_value);
 
 #define S48_EXTRACT_VALUE_POINTER(x, type) ((type *) s48_value_pointer(x))
diff --git a/scheme/link/generate-c-header.scm b/scheme/link/generate-c-header.scm
index 4fb441a..122ffa9 100644
--- a/scheme/link/generate-c-header.scm
+++ b/scheme/link/generate-c-header.scm
@@ -122,9 +122,9 @@
     (c-define (string-append
 	       "S48_STOB_BYTE_SET(x, i, v) "
 	       "do { "
-	       "char __stob_set_x = (x); "
+	       "s48_value __stob_set_x = (x); "
 	       "long __stob_set_i = (i); "
-	       "s48_value __stob_set_v = (v); "
+	       "char __stob_set_v = (v); "
 	       "if (S48_STOB_IMMUTABLEP(__stob_set_x)) "
 	       "s48_raise_argtype_error(__stob_set_x); "
 	       "else "
@@ -188,7 +188,7 @@
 			  type type)
 		(c-define "S48_UNSAFE_~A_REF(x, i) (S48_STOB_BYTE_REF((x), (i)))"
 			  type)
-		(c-define "S48_UNSAFE_~A_SET(x, i, v) S48_BYTE_STOB_SET((x), (i), (v))"
+		(c-define "S48_UNSAFE_~A_SET(x, i, v) S48_STOB_BYTE_SET((x), (i), (v))"
 			  type))
 	      '("BYTE_VECTOR" "STRING"))
     (c-define "S48_UNSAFE_BYTE_VECTOR_LENGTH(x) (S48_STOB_BYTE_LENGTH(x))")