1 #include <fcntl.h> 2 #include <unistd.h> 3 #include <sys/uio.h> 4 #include <assert.h> 5 6 int 7 main(void) 8 { 9 const off_t offset = 0xdefaceddeadbeefLL; 10 int fd; 11 char buf[4]; 12 struct iovec iov = { buf, sizeof buf }; 13 14 assert((fd = open("/dev/zero", O_RDONLY)) >= 0); 15 assert(pread(fd, buf, sizeof buf, offset) == 4); 16 assert(preadv(fd, &iov, 1, offset) == 4); 17 assert(!close(fd)); 18 19 assert((fd = open("/dev/null", O_WRONLY)) >= 0); 20 assert(pwrite(fd, buf, sizeof buf, offset) == 4); 21 assert(pwritev(fd, &iov, 1, offset) == 4); 22 assert(!close(fd)); 23 24 return 0; 25 } 26
