4.c

 

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
    int fd;
    int ret;
    if (argc < 2)
    {
        fprintf(stderr, "Usage: %s filename\n", argv[0]);
        return -1;
    }
    fd = open(argv[1], O_RDWR);
    if (fd == -1)
    {
        perror("open");
        return -1;
    }
    ret = lseek(fd, 1 * 1024 * 1024 * 1024, SEEK_END);
    printf("ret = %d\n", ret);
    ret = write(fd, "", 1);
    printf("ret = %d\n", ret);
    close(fd);
    return -1;
}