c_cpp C中流对象的一个​​实现

Posted 2021-05-14

#include <stdio.h>
#include <stdlib.h>

// example of dynamic stream objects

typedef struct
{
	size_t size;
	int type;
	// Allows custom sizing of object
	unsigned char item[0];
} StreamObj;


int main(int argc, char const *argv[])
{
	printf("the size is %lu\n", sizeof(StreamObj));
	unsigned char foo[0];
	printf("the size of foo is %lu\n", sizeof(foo));
	StreamObj* ptr = malloc(sizeof(StreamObj) + 10);
	ptr->size = sizeof(StreamObj) + 10;
	ptr->item[0] = 3;
	ptr->item[1] = 5;
	ptr->item[2] = 6;
	printf("First three elems are %u, %u and %u\n", ptr->item[0], ptr->item[1], ptr->item[2]);
	free(ptr);
	return 0;
}