3.1 测试能否对标准输入设置偏移量

file/seek.c

#include "apue.h"
int
main(void)
{
	if (lseek(STDIN_FILENO, 0, SEEK_CUR) == -1)
		printf("cannot seek\n");
	else
		printf("seek OK\n");
	exit(0);
}