diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 4689f3a..a2a1640 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -50,6 +50,11 @@
     !defined(MBEDTLS_PLATFORM_SNPRINTF_MACRO)
 #define MBEDTLS_PLATFORM_SNPRINTF_ALT
 #endif
+
+#if !defined(MBEDTLS_PLATFORM_VSNPRINTF_ALT) && \
+    !defined(MBEDTLS_PLATFORM_VSNPRINTF_MACRO)
+#define MBEDTLS_PLATFORM_VSNPRINTF_ALT
+#endif
 #endif /* _WIN32 */
 
 #if defined(TARGET_LIKE_MBED) && \