#include "fast_float/fast_float.h" double get(char const *input) { double result_value; auto result = fast_float::from_chars(input, input + strlen(input), result_value); if (result.ec != std::errc()) { return 10; } return result_value; } int main(int arg, char **argv) { double x = get(argv[0]); return int(x); }