diff --git a/base_class/string/EST_strcasecmp.c b/base_class/string/EST_strcasecmp.c
index 72a9b7c..e196c3a 100755
--- a/base_class/string/EST_strcasecmp.c
+++ b/base_class/string/EST_strcasecmp.c
@@ -86,7 +86,7 @@ static const unsigned char def_charmap[] = {
 int
 EST_strcasecmp(const char *s1, const char *s2, const unsigned char *charmap)
 {
-	register const unsigned char *cm = charmap?charmap:def_charmap,
+	const unsigned char *cm = charmap?charmap:def_charmap,
 			*us1 = (const unsigned char *)s1,
 			*us2 = (const unsigned char *)s2;
 	int r;
@@ -102,7 +102,7 @@ int
 EST_strncasecmp(const char *s1, const char *s2, size_t n, const unsigned char *charmap)
 {
 	if (n != 0) {
-		register const unsigned char *cm = charmap?charmap:def_charmap,
+		const unsigned char *cm = charmap?charmap:def_charmap,
 				*us1 = (const unsigned char *)s1,
 				*us2 = (const unsigned char *)s2;
 
diff --git a/base_class/string/regexp.cc b/base_class/string/regexp.cc
index 8b8f15f..c6211fa 100644
--- a/base_class/string/regexp.cc
+++ b/base_class/string/regexp.cc
@@ -175,7 +175,7 @@ STATIC char *regbranch(int *flagp);
 STATIC char *regpiece(int *flagp);
 STATIC char *regatom(int *flagp);
 STATIC char *regnode(char op);
-STATIC char *regnext(register char *p);
+STATIC char *regnext(char *p);
 STATIC void regc(char b);
 STATIC void reginsert(char op, char *opnd);
 STATIC void regtail(char *p, char *val);
diff --git a/base_class/string/regsub.c b/base_class/string/regsub.c
index 017cea2..ed7cc9b 100644
--- a/base_class/string/regsub.c
+++ b/base_class/string/regsub.c
@@ -38,11 +38,11 @@ const hs_regexp *prog;
 const char *source;
 char *dest;
 {
-	register char *src;
-	register char *dst;
-	register char c;
-	register int no;
-	register int len;
+	char *src;
+	char *dst;
+	char c;
+	int no;
+	int len;
 
 	if (prog == NULL || source == NULL || dest == NULL) {
 		hs_regerror("NULL parm to regsub");