1 /*
2 ============================================================================
3 Name : test.c
4 Author : blank
5 Version :
6 Copyright : Your copyright notice
7 Description : 程序3-4 对指定的描述符打印文件标志
8 ============================================================================
9 */
10
11 #include <stdio.h>
12 #include <fcntl.h>
13 #include <stdlib.h>
14 #include "ourhdr.h"
15
16 int main(int argc, char *argv[])
17 {
18 int val;
19
20 if (argc != 2){
21 err_quit("usage: ./test <descriptor#>");
22 }
23
24 if ((val = fcntl(atoi(argv[1]), F_GETFD, 0)) < 0){
25 err_sys("fcntl error for fd: %d\n", atoi(argv[1]));
26 }
27
28 switch(val & O_ACCMODE){
29 case O_RDONLY:
30 printf("read only");
31 break;
32 case O_WRONLY:
33 printf("write only");
34 break;
35 case O_RDWR:
36 printf("read write");
37 break;
38 default:
39 err_dump("unknown access mode");
40 }
41
42 if (val & O_APPEND){
43 printf(", append");
44 }
45
46 if(val & O_NONBLOCK){
47 printf(", nonblock");
48 }
49 #if defined(O_SYNC)
50 if (val & O_SYNC){
51 printf(", synchronous writes");
52 }
53 #endif
54
55 #if !defined(_POSIX_C_SOURCE) && defined(O_FSYN)
56 if (val & O_FSYN){
57 printf(", synchronous writes.");
58 }
59 #endif
60
61 putchar('\n');
62 exit(0);
63 }
