diff -Naru speech_tools_orig/siod/editline.c speech_tools/siod/editline.c
--- speech_tools_orig/siod/editline.c	2025-07-01 09:07:39.174350577 +0900
+++ speech_tools/siod/editline.c	2025-07-01 09:16:17.654869747 +0900
@@ -176,7 +176,7 @@
 STATIC STATUS h_prev();
 STATIC STATUS h_first();
 STATIC STATUS h_last();
-STATIC int substrcmp(char *text, char *pat, int len);
+STATIC int substrcmp(const char *text, const char *pat, long unsigned int len);
 STATIC ECHAR *search_hist(ECHAR *search, ECHAR *(*move)());
 STATIC STATUS h_search();
 STATIC STATUS fd_char();
@@ -792,7 +792,7 @@
 /*
 **  Return zero if pat appears as a substring in text.
 */
-STATIC int substrcmp(char *text, char *pat, int len)
+STATIC int substrcmp(const char *text, const char *pat, long unsigned int len)
 {
     ECHAR	c;
 
@@ -809,7 +809,7 @@
     static ECHAR	*old_search;
     int		len;
     int		pos;
-    int		(*match)();
+    int		(*match)(const char *, const char *, long unsigned int);
     char	*pat;
 
     /* Save or get remembered search pattern. */