#include <sys/uio.h>#include <stdio.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <fcntl.h>intmain(){int fd = open("testfile", O_CREAT | O_RDWR, 0666);if (fd < 0) {printf("file open error %s\n", strerror(errno));return 1;}int dummy;int ret;iovec vec1 = { &dummy, sizeof(dummy) };ret = writev(fd, &vec1, 0x80000001);if (ret < 0) {printf("vec 1 write error %s\n", strerror(errno));}iovec vec2 = { (void *)0x80100000, 0x1000 };ret = writev(fd, &vec2, 1);if (ret < 0) {printf("vec 2 write error %s\n", strerror(errno));}iovec vec3 = { 0, 1 };ret = writev(fd, &vec3, 0xfff);if (ret < 0) {printf("vec 3 write error %s\n", strerror(errno));}close(fd);return 0;}