diff --git a/Basic2/MSDOS/basic.c b/Basic2/MSDOS/basic.c
index 9cb387f..e4fff7e 100644
--- a/Basic2/MSDOS/basic.c
+++ b/Basic2/MSDOS/basic.c
@@ -1608,7 +1608,7 @@ void storecstring(address_t ax, address_t s, char* b) {
 
 /* length of a c string up to a limit l */
 address_t cstringlength(char* c, address_t l) {
-	address_t a;
+	address_t a = 0;
 
 	while(a < l && c[a] != 0) a++;
 	return a;
diff --git a/Basic2/Posix/basic.c b/Basic2/Posix/basic.c
index f17dd20..81890b2 100755
--- a/Basic2/Posix/basic.c
+++ b/Basic2/Posix/basic.c
@@ -1836,7 +1836,7 @@ void storecstring(address_t ax, address_t s, char* b) {
 
 /* length of a c string up to a limit l */
 address_t cstringlength(char* c, address_t l) {
-  address_t a;
+  address_t a = 0;
 
   while (a < l && c[a] != 0) a++;
   return a;
diff --git a/Basic2/RaspPi/basic.c b/Basic2/RaspPi/basic.c
index 35b352e..6c8f6cb 100755
--- a/Basic2/RaspPi/basic.c
+++ b/Basic2/RaspPi/basic.c
@@ -1657,7 +1657,7 @@ void storecstring(address_t ax, address_t s, char* b) {
 
 /* length of a c string up to a limit l */
 address_t cstringlength(char* c, address_t l) {
-	address_t a;
+	address_t a = 0;
 
 	while(a < l && c[a] != 0) a++;
 	return a;
diff --git a/Basic2/Windows/basic.c b/Basic2/Windows/basic.c
index 35b352e..6c8f6cb 100755
--- a/Basic2/Windows/basic.c
+++ b/Basic2/Windows/basic.c
@@ -1657,7 +1657,7 @@ void storecstring(address_t ax, address_t s, char* b) {
 
 /* length of a c string up to a limit l */
 address_t cstringlength(char* c, address_t l) {
-	address_t a;
+	address_t a = 0;
 
 	while(a < l && c[a] != 0) a++;
 	return a;