我使用Boost Program Options Library来解析命令行参数。
我有以下要求:
我该如何处理这件事?这是我的代码来处理这个,我发现它是非常冗余的,我想一定有一个容易做的,对吧?
#include <boost/program_options.hpp>
#include <iostream>
#include <sstream>
namespace po = boost::program_options;
bool process_command_line(int argc, char** argv,
std::string& host,
std::string& port,
std::string& configDir)
{
int iport;
try
{
po::options_description desc("Program Usage", 1024, 512);
desc.add_options()
("help", "produce help message")
("host,h", po::value<std::string>(&host), "set the host server")
("port,p", po::value<int>(&iport), "set the server port")
("config,c", po::value<std::string>(&configDir), "set the config path")
;
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
po::notify(vm);
if (vm.count("help"))
{
std::cout << desc << "\n";
return false;
}
// There must be an easy way to handle the relationship between the
// option "help" and "host"-"port"-"config"
if (vm.count("host"))
{
std::cout << "host: " << vm["host"].as<std::string>() << "\n";
}
else
{
std::cout << "\"host\" is required!" << "\n";
return false;
}
if (vm.count("port"))
{
std::cout << "port: " << vm["port"].as<int>() << "\n";
}
else
{
std::cout << "\"port\" is required!" << "\n";
return false;
}
if (vm.count("config"))
{
std::cout << "config: " << vm["config"].as<std::string>() << "\n";
}
else
{
std::cout << "\"config\" is required!" << "\n";
return false;
}
}
catch(std::exception& e)
{
std::cerr << "Error: " << e.what() << "\n";
return false;
}
catch(...)
{
std::cerr << "Unknown error!" << "\n";
return false;
}
std::stringstream ss;
ss << iport;
port = ss.str();
return true;
}
int main(int argc, char** argv)
{
std::string host;
std::string port;
std::string configDir;
bool result = process_command_line(argc, argv, host, port, configDir);
if (!result)
return 1;
// Do the main routine here
}
发布于 2011-04-02 03:09:14
我自己也遇到过这个问题。解决方案的关键是po::store
函数填充variables_map
,而po::notify
引发遇到的任何错误,因此可以在发送任何通知之前使用vm
。
因此,按照Tim,根据需要将每个选项设置为required,但在处理完help选项之后运行po::notify(vm)
。这样它就会退出,不会抛出任何异常。现在,将选项设置为required后,缺少的选项将导致抛出required_option
异常,并且使用其get_option_name
方法可以将错误代码减少为相对简单的catch
块。
另外,您的选项变量是通过po::value< -type- >( &var_name )
机制直接设置的,因此您不必通过vm["opt_name"].as< -type- >()
访问它们。
Peters answer中提供了一个代码示例
发布于 2011-04-02 05:44:45
以下是根据rcollyer和Tim的完整计划,他们将获得学分:
#include <boost/program_options.hpp>
#include <iostream>
#include <sstream>
namespace po = boost::program_options;
bool process_command_line(int argc, char** argv,
std::string& host,
std::string& port,
std::string& configDir)
{
int iport;
try
{
po::options_description desc("Program Usage", 1024, 512);
desc.add_options()
("help", "produce help message")
("host,h", po::value<std::string>(&host)->required(), "set the host server")
("port,p", po::value<int>(&iport)->required(), "set the server port")
("config,c", po::value<std::string>(&configDir)->required(), "set the config path")
;
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
if (vm.count("help"))
{
std::cout << desc << "\n";
return false;
}
// There must be an easy way to handle the relationship between the
// option "help" and "host"-"port"-"config"
// Yes, the magic is putting the po::notify after "help" option check
po::notify(vm);
}
catch(std::exception& e)
{
std::cerr << "Error: " << e.what() << "\n";
return false;
}
catch(...)
{
std::cerr << "Unknown error!" << "\n";
return false;
}
std::stringstream ss;
ss << iport;
port = ss.str();
return true;
}
int main(int argc, char** argv)
{
std::string host;
std::string port;
std::string configDir;
bool result = process_command_line(argc, argv, host, port, configDir);
if (!result)
return 1;
// else
std::cout << "host:\t" << host << "\n";
std::cout << "port:\t" << port << "\n";
std::cout << "config:\t" << configDir << "\n";
// Do the main routine here
}
/* Sample output:
C:\Debug>boost.exe --help
Program Usage:
--help produce help message
-h [ --host ] arg set the host server
-p [ --port ] arg set the server port
-c [ --config ] arg set the config path
C:\Debug>boost.exe
Error: missing required option config
C:\Debug>boost.exe --host localhost
Error: missing required option config
C:\Debug>boost.exe --config .
Error: missing required option host
C:\Debug>boost.exe --config . --help
Program Usage:
--help produce help message
-h [ --host ] arg set the host server
-p [ --port ] arg set the server port
-c [ --config ] arg set the config path
C:\Debug>boost.exe --host 127.0.0.1 --port 31528 --config .
host: 127.0.0.1
port: 31528
config: .
C:\Debug>boost.exe -h 127.0.0.1 -p 31528 -c .
host: 127.0.0.1
port: 31528
config: .
*/
发布于 2011-04-02 02:27:05
您可以很容易地指定某个选项是必需的[1],例如:
..., value<string>()->required(), ...
但据我所知,没有办法将不同选项之间的关系表示到program_options库中。
一种可能性是使用不同的选项集多次解析命令行,如果您已经检查了"help“,则可以根据需要再次解析其他三个选项。不过,我不确定我会不会认为这比你所拥有的有所改善。
https://stackoverflow.com/questions/5395503
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