1 files changed, 1 insertions, 1 deletions
diff --git a/sprintf.c b/sprintf.c
index cf8ea20de6..d8aa5fd0a4 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -718,7 +718,7 @@ rb_f_sprintf(argc, argv)
 		fval = RFLOAT(rb_Float(val))->value;
 #if defined(_WIN32) && !defined(__BORLANDC__)
 		if (isnan(fval) || isinf(fval)) {
-		    char *expr;
+		    const char *expr;
 
 		    if  (isnan(fval)) {
 			expr = "NaN";