#include <assert.h>
#include <random>

std::random_device rd;
typedef std::mt19937 RandEngine;
//RandEngine e(std::random_device()());
RandEngine e(rd());
//Generate long random binary result
void genrand(void *dest, size_t n) {
    typedef uint32_t res_t;
    assert(n >= sizeof(res_t) &&
        "This function is designed for generating long random binary result, please use other function");
    assert(n % sizeof(res_t) == 0);
    
    res_t *i = reinterpret_cast<res_t *>(dest);
    res_t *j = reinterpret_cast<res_t *>((uint8_t*)dest + n);
    for (; i < j; ++i) {
        *i = e();
    }
}

坑点

不能

typedef RandEngine::result_type res_t;

因为标准库里的mt19937是用来生成32bit的伪随机数的，而​​RandEngine::result_type​​有可能是64bit的。

参考

​​http://www.cplusplus.com/reference/random/mt19937/​​​​What is uint_fast32_t and why should it be used instead of the regular int and uint32_t?​​