Don't hardcode message length
diff --git a/src/video/vita/SDL_vitamessagebox.c b/src/video/vita/SDL_vitamessagebox.c
index 09c8ae1..a3969d7 100644
--- a/src/video/vita/SDL_vitamessagebox.c
+++ b/src/video/vita/SDL_vitamessagebox.c
@@ -53,7 +53,7 @@ int VITA_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid)
param.mode = SCE_MSG_DIALOG_MODE_USER_MSG;
SDL_zero(msgParam);
- SDL_snprintf(message, 512, "%s\r\n\r\n%s", messageboxdata->title, messageboxdata->message);
+ SDL_snprintf(message, sizeof(message), "%s\r\n\r\n%s", messageboxdata->title, messageboxdata->message);
msgParam.msg = (const SceChar8*)message;
SDL_zero(buttonParam);