C++ - 所有隐式转换的编译错误

Question

是否有编译器标志在任何隐式转换(如 int32_t 到 uint32_t)的情况下记录警告/错误。

#include <cstdint>
#include <iostream>


using ::std::int32_t;
using ::std::uint32_t;


int main(int argc, char *argv[])
{

   int32_t x = 9;

    uint32_t i = x;

    std::cout << " " << x << " " << i << std::flush << std::endl;

    return 0;
}

c++ -std=c++11 -Wall -Wconversion -Wpedantic cast.cpp

我在编译期间没有遇到任何问题/警告/错误 - 有没有办法可以实现。

Answer 1

uint32_t i = x;

Signed int 类型到 unsigned int 类型的转换在 C++ 中有明确的定义。

(C++11，§4.7 ¶2)

If the destination type is unsigned, the resulting value is the least unsigned integer congruent to the source integer (modulo 2ⁿ where n is the number of bits used to represent the unsigned type). [ Note: In a two’s complement representation, this conversion is conceptual and there is no change in the bit pattern (if there is no truncation). — end note ]