#include <stdio.h>
#include <sys/types.h>
#include <error.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>

int main()
{
	int file;
	int ret;
	char buf[0x100];

	file = open("/tmp/work.c", O_RDONLY);
	if (file == -1) {
		printf("\nopen file failed. errno = %d\n", errno);
		goto err;
	} else
		printf("\nopen file succeed.\n");

	printf("before unreachable\n");
	__builtin_unreachable();
	printf("after unreachable\n");

	if (lseek(file, 10, SEEK_END) < 0) {
		printf("\nlseek file failed. errno = %d\n", errno);
		goto err;
	}

	ret = read(file, buf, 0x100);
	if (ret < 0) {
		printf("\n1st read file failed. errno = %d, ret = %d\n", errno, ret);
		goto err;
	} else
		printf("\n1st read file succeed. errno = %d, ret = %d\n", errno, ret);

	ret = read(file, buf, 0x100);
	if (ret < 0) {
		printf("\n2nd read file failed. errno = %d, ret = %d\n", errno, ret);
		goto err;
	} else
		printf("\n2nd read file succeed. errno = %d, ret = %d\n", errno, ret);

	ret = read(file, buf, 0x100);
	if (ret < 0) {
		printf("\n2rd read file failed. errno = %d, ret = %d\n", errno, ret);
		goto err;
	} else
		printf("\n3rd read file succeed. errno = %d, ret = %d\n", errno, ret);


	return 0;
err:
	return -1;
}