提高program_options多个值的问题 [英] boost program_options multiple values problem
问题描述
所以我工作过的用于升压program_options库中的一个例子,我想尝试的多值/矢量值中的一个设定的默认值,但它似乎并没有工作。因为我认为这是<一个href=\"http://old.nabble.com/-boost---program-options--Recommended-way-to-specify-a-list-of-strings-td26881411.html\">suggested在这里工作的。
我已经修改是约40行:
PO :: options_description配置(配置);
config.add_options()
(优化,PO ::值&LT; INT&GT;(安培; OPT) - &GT; DEFAULT_VALUE(10)
优化级别)
(包括路径,I,邻::值&LT;矢量&lt;串&GT;&GT;() - GT; DEFAULT_VALUE(矢量&lt;串&GT;(),东西) - GT;构成(),包括路径)
;
当我编译这个小小的改变,我希望在没有-I选项传递的东西被添加到包括路径参数列表。
没有人有任何想法,为什么这是不是这样?
下面是完整的源$ C $ C:
的#include&LT;升压/ program_options.hpp&GT;
命名空间PO =的boost :: program_options;
#包括LT&;&iostream的GT;
#包括LT&;&的fstream GT;
#包括LT&;&迭代器GT;
使用命名空间std;//一个辅助函数来简化主要部分。
模板&LT;类T&GT;
ostream的&安培;运营商的LT;≤(ostream的&安培; OS,常量矢量&lt; T&GT;&安培; 5)
{
副本(v.begin(),v.end(),ostream_iterator&LT; T&GT;(COUT,));
返回操作系统;
}
INT主(INT交流,字符* AV [])
{
尝试{
INT选择; //声明一组,这将是选项
//只允许在命令行
PO :: options_description通用(通用选项);
generic.add_options()
(版本,V,印刷版字符串)
(帮助,生产帮助信息)
; //声明一组,这将是选项
//允许无论在命令行和
//配置文件
PO :: options_description配置(配置);
config.add_options()
(优化,PO ::值&LT; INT&GT;(安培; OPT) - &GT; DEFAULT_VALUE(10)
优化级别)
(包括路径,我
PO ::值&LT;矢量&lt;字符串&GT; &GT;() - GT; DEFAULT_VALUE(矢量&lt;串GT;(),东西) - GT;构成()
包括路径)
; //隐藏选项,将在命令行中都允许和
//在配置文件中,但将不显示给用户。
PO :: options_description隐藏(隐藏选项);
hidden.add_options()
(输入文件,PO ::值&LT;矢量&lt;串GT;&GT;(),输入文件)
;
PO :: options_description cmdline_options;
cmdline_options.add(通用)。新增(配置)。新增(隐藏); PO :: options_description config_file_options;
config_file_options.add(配置)。新增(隐藏); PO :: options_description可见(允许的选项);
visible.add(通用)。新增(配置); PO :: positional_options_description磷;
p.add(输入文件,-1); PO :: variables_map VM;
存储(PO :: command_line_parser(AC,AV)。
选项(cmdline_options).positional(P).RUN(),VM); ifstream的IFS(multiple_sources.cfg);
存储(parse_config_file(IFS,config_file_options),VM);
通知(VM); 如果(vm.count(帮助)){
COUT&LT;&LT;可见&LT;&LT; \\ n;
返回0;
} 如果(vm.count(版本)){
COUT&LT;&LT; 多源为例,1.0版\\ n;
返回0;
} 如果(vm.count(包括路径))
{
COUT&LT;&LT; 包括路径是:
&LT;&LT; VM [包括路径]为&lt;矢量&lt;字符串&GT; &GT;()&LT;&LT; \\ n;
} 如果(vm.count(输入文件))
{
COUT&LT;&LT; 输入文件是:
&LT;&LT; VM [输入文件]为&lt;矢量&lt;字符串&GT; &GT;()&LT;&LT; \\ n;
} COUT&LT;&LT; 优化级别为&LT;&LT;选择&LT;&LT; \\ n;
}
赶上(例外急症)
{
COUT&LT;&LT; e.what()&所述;&下; \\ n;
返回1;
}
返回0;
}
对于DEFAULT_VALUE的方法,第一个参数是你希望你的选择是真正的价值,第二个值仅为文本重新presentation(在--help显示)时,升压不能推断它。
所以,解决你的问题是这样写:
PO ::值&LT;矢量&lt;字符串&GT; &GT;() - GT; DEFAULT_VALUE(
矢量&lt;串GT;(1,东西),东西) - GT;构成()
这样,你说的,默认值是单个元素东西的载体,以及要显示的帮助东西,如:
配置:
--optimization ARG(= 10)优化级
-I [--include路径] ARG(=东西)
包含路径
So I'm working off one of the examples for Boost program_options library, and I wanted to try setting a default value for one of the multiple-values/ vector-values, but it doesn't seem to work. As I think is suggested here to work.
What I've modified is on about line 40:
po::options_description config("Configuration");
config.add_options()
("optimization", po::value<int>(&opt)->default_value(10),
"optimization level")
("include-path,I", o::value< vector<string> >()->default_value(vector<string>(),"SOMETHING")->composing(), "include path")
;
When I compile this small change, I expect that when no -I option is passed that the "SOMETHING" is added to the include-path argument list.
Does anyone have any idea why this is not the case?
Here is the complete source code:
#include <boost/program_options.hpp>
namespace po = boost::program_options;
#include <iostream>
#include <fstream>
#include <iterator>
using namespace std;
// A helper function to simplify the main part.
template<class T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
copy(v.begin(), v.end(), ostream_iterator<T>(cout, " "));
return os;
}
int main(int ac, char* av[])
{
try {
int opt;
// Declare a group of options that will be
// allowed only on command line
po::options_description generic("Generic options");
generic.add_options()
("version,v", "print version string")
("help", "produce help message")
;
// Declare a group of options that will be
// allowed both on command line and in
// config file
po::options_description config("Configuration");
config.add_options()
("optimization", po::value<int>(&opt)->default_value(10),
"optimization level")
("include-path,I",
po::value< vector<string> >()->default_value(vector<string>(),"SOMETHING")->composing(),
"include path")
;
// Hidden options, will be allowed both on command line and
// in config file, but will not be shown to the user.
po::options_description hidden("Hidden options");
hidden.add_options()
("input-file", po::value< vector<string> >(), "input file")
;
po::options_description cmdline_options;
cmdline_options.add(generic).add(config).add(hidden);
po::options_description config_file_options;
config_file_options.add(config).add(hidden);
po::options_description visible("Allowed options");
visible.add(generic).add(config);
po::positional_options_description p;
p.add("input-file", -1);
po::variables_map vm;
store(po::command_line_parser(ac, av).
options(cmdline_options).positional(p).run(), vm);
ifstream ifs("multiple_sources.cfg");
store(parse_config_file(ifs, config_file_options), vm);
notify(vm);
if (vm.count("help")) {
cout << visible << "\n";
return 0;
}
if (vm.count("version")) {
cout << "Multiple sources example, version 1.0\n";
return 0;
}
if (vm.count("include-path"))
{
cout << "Include paths are: "
<< vm["include-path"].as< vector<string> >() << "\n";
}
if (vm.count("input-file"))
{
cout << "Input files are: "
<< vm["input-file"].as< vector<string> >() << "\n";
}
cout << "Optimization level is " << opt << "\n";
}
catch(exception& e)
{
cout << e.what() << "\n";
return 1;
}
return 0;
}
For the "default_value" method, the first parameter is the real value that you wish your option to be, the second value being only the textual representation (for display in --help) when boost cannot infer it.
So, the solution to your problem is to write:
po::value< vector<string> >()->default_value(
vector<string>(1, "SOMETHING"), "SOMETHING")->composing(),
This way, you are saying that the default value is a vector with a single element "SOMETHING", and that you want to display "SOMETHING" in the help, such as:
Configuration:
--optimization arg (=10) optimization level
-I [ --include-path ] arg (=SOMETHING)
include path
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