diff --git a/armsrc/printf.h b/armsrc/printf.h
index 21d9c8fa4..616752ed6 100644
--- a/armsrc/printf.h
+++ b/armsrc/printf.h
@@ -16,7 +16,7 @@
 #include "string.h"
 
 int kvsprintf(const char *format, void *arg, int radix, va_list ap) __attribute__((format(printf, 1, 0)));
-int vsprintf(char *str, const char *format, va_list ap) __attribute__((format(printf, 2, 0)));
-int sprintf(char *str, const char *format, ...) __attribute__((format(printf, 2, 3)));
+int vsprintf(char *dest, const char *fmt, va_list ap) __attribute__((format(printf, 2, 0)));
+int sprintf(char *dest, const char *fmt, ...) __attribute__((format(printf, 2, 3)));
 
 #endif