malloc分配内存好奇怪

Question

这个malloc函数为什么和假的一样，我不管分配多少字节他都可以一样啊，我甚至malloc 1个字节都可以一样运行？？

Answer 1

malloc returns a void pointer to the allocated space, or NULL if there is insufficient memory available. To return a pointer to a type other than void, use a type cast on the return value. The storage space pointed to by the return value is guaranteed to be suitably aligned for storage of any type of object. If size is 0, malloc allocates a zero-length item in the heap and returns a valid pointer to that item. Always check the return from malloc, even if the amount of memory requested is small.

另外，“malloc() 在分配内存的时候，并不是老老实实按用户预期申请的字节数来分配内存空间大小，而是会预分配更大的空间作为内存池。具体会预分配多大的空间，跟 malloc 使用的内存管理器有关系。”