c语言中的getopt()、optind的使用

getopt()会在最后一次执行时将argv变量进行排序，将参数（“d:t”）中提到的变量排序到最前面。这样后面的argc、argv变量通过optind计算就会非常清楚，经过遍历getopt()之后的参数就是没有被指定顺序的。

#include<stdio.h>#include<unistd.h>void print_arg(int argc, char *argv[]){    int i = 0;    printf("----START PRINT----\n");    for (i = 0; i< argc; i++)    {        printf("%d\t%s\n", i, argv[i]);    }}int main(int argc, char *argv[]){    char *delivery = "";    int thick = 0;    int count = 0;    char ch;    while((ch = <span style="color:#CC33CC;">getopt(argc, argv, "d:t")</span>) != EOF)    {        print_arg(argc, argv);        switch(ch)        {            case 'd':                delivery = optarg;                break;            case 't':                thick = 1;                break;            default:                fprintf(stderr, "Unknown option: '%s'\n", optarg);                return 1;        }    }    print_arg(argc, argv);    argc -= optind;    argv += optind;    printf("OPTIND:%d\n", optind);    print_arg(argc, argv);    return 0;}

---

程序执行的结果：

x_think@swork0:~$ gcc p152.c -o p152 && ./p152 -d now Anchovies Pineapple -t
----START PRINT----
0     ./p152
1     -d
2     now
3     Anchovies
4     Pineapple
5     -t
----START PRINT----
0     ./p152
1     -d
2     now
3     Anchovies
4     Pineapple
5     -t
----START PRINT----
0     ./p152
1     -d
2     now
3     -t
4     Anchovies
5     Pineapple
OPTIND:4
----START PRINT----
0     Anchovies
1     Pineapple

代码片段来自 Head First C, by David Griffiths and Dawn Griffiths. Copyright © 2012 David Griffiths and Dawn Griffiths. All rights reserved. ISBN: 978-1-449-39991-7 引用时有删节