getopt_long无法正确处理我的参数 [英] getopt_long doesnt handle my arguments right

问题描述

int next_option;
int keep_content =0;
int option_index = 0;
const string short_options = "c::";


 const struct option long_options[] = 
{ 

    {"config", optional_argument, NULL, 'c'},
    {"keep", no_argument, &keep_content, 1},
    { NULL,0, NULL, 0}
};

while((next_option = getopt_long(argc,argv,short_options.c_str(),long_options,&option_index))!= -1)
{
    cout << "name: " << long_options[option_index].name  << " " << "value: " << optarg << endl;
    cout << "keep_content: " << keep_content << endl;
}

我在上面的代码中尝试测试参数并切换解析.进行了以下测试:

I have the above code where iam trying to test argument and switch parsing. The following test were made:

a.out -chey  --> name: config value: hey  //which is correct 
a.out -c hey  --> name:  value:           //what's wrong?
a.out --confighey  --> name:  value:      //what's wrong?
a.out --config hey  --> name:  value:     //what's wrong?
a.out -chey --keep  --> name: config value: hey  keep_content: 0 // what's wrong? keep_content should be 1

能否请您帮我了解正确的用法?我在做什么错了?

can you please help me understand the correct usage? what am i doing wrong?

谢谢您的时间

推荐答案

您期望有一个可选参数，并根据man 3 getopt:

You are expecting an optional argument and according to man 3 getopt:

optstring是包含合法选项字符的字符串.如果此类字符后接冒号，则该选项需要一个参数，因此getopt()会放置一个 指向同一argv-element中以下文本的指针，或optarg中以下argv-element文本的指针. 两个冒号表示一个选项带有一个可选的arg；如果有 当前argv元素中的文本(即与选项名称本身相同的词，例如"-oarg")，然后以optarg返回，否则optarg设置为零. 这是一个GNU扩展.如果optstring包含W后跟一个分号，则-W foo被视为long选项--foo. (-W选项由POSIX.2保留用于 实施扩展.)

optstring is a string containing the legitimate option characters. If such a character is followed by a colon, the option requires an argument, so getopt() places a pointer to the following text in the same argv-element, or the text of the following argv-element, in optarg. Two colons mean an option takes an optional arg; if there is text in the current argv-element (i.e., in the same word as the option name itself, for example, "-oarg"), then it is returned in optarg, otherwise optarg is set to zero. This is a GNU extension. If optstring contains W followed by a semicolon, then -W foo is treated as the long option --foo. (The -W option is reserved by POSIX.2 for implementation extensions.)

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