c++ - 解决 C++ 'target of assignment not really an lvalue' 错误

Question

给定这段代码:

void FrMemCopy(void *to, const void *from, size_t sz)
{
    size_t sz8 = sz >> 3;
    size_t sz1 = sz - (sz8 << 3);

    while (sz8-- != 0) {
        *((double *)to)++ = *((double *)from)++;
    }

    while (sz1-- != 0) {
        *((char *)to)++ = *((char *)from)++;
    }
}

我在 while 循环内的两行收到 target of assignment not really an lvalue 警告。

谁能打破这些界限？

强制转换然后增量？

什么是更简单的写法？

错误是什么意思？

Answer 1

它不喜欢 *((char*)to)++ 语句。

试试这个:

void FrMemCopy(void *to, const void *from, size_t sz)
{
    size_t sz8 = sz >> 3;
    size_t sz1 = sz - (sz8 << 3);
    double * tod = (double *) to;
    double * fromd = (double *) from;
    while (sz8-- != 0) {
        *(tod++) = *(fromd++);
    }

    char * toc = (char *) tod;
    char * fromc = (char *) fromd;
    while (sz1-- != 0) {
        *(toc++) = *(fromc++);
    }
}