3 ms·

This isn’t exactly surprising. With functions like printf and scanf you always have to be super careful to pass the right data types. It may work with one OS or

• monocasa 7y ago
  At least for printf, there's normally a way to tell the compiler that it's a printf style interface and get something approaching typesafety back. On gcc this is extern int my_printf (void *my_object, const char *my_format, ...) __attribute__ ((format (printf, 2, 3))); (Now I like rust's solution better, a sane macro system so this interface doesn't have to be special cased by the compiler to be safe).
  • jdashg 7y ago
    This is best-practice. Varargs will bite you if you don't have the compiler check your work, but fortunately they're happy to do so these days.
  • DerekL 7y ago
    C++20 is adding a type-safe alternative to printf, called std::format, though it doesn't provide warnings at compile time.
    • Ididntdothis 7y ago
      They should have gone step further and done string interpolation how C# and JS can do. Really nice to use and avoids errors.
    • excessive 7y ago
      Here's one you can use with (pretty much) any version of C++: __attribute__ ((format (printf, 1, 2))) static inline std::string format(const char* fmt, ...) { va_list args; va_start(args, fmt); size_t bytes = vsnprintf(0, 0, fmt, args); va_end(args); va_list again; va_start(again, fmt); std::string result(bytes, '\0'); vsnprintf(&result[0], bytes + 1, fmt, again); va_end(again); return result; }