boost_program_options

boost_program_options

Author:	wisut hantanong
Version:	0.1

Contents

• Introduction
• Declaration
  • Named options
  • Position options
• store() function

Introduction

boost program_options allowed program to get command line arguments and from configuration file.

There are two types of options in this sample code

1. Named option
2. Position option

Declaration

Named options

Named options declare via boost::program_options::options_description

name	type	default value
help	string	NUll
string	string	NULL
int	int	0

The following code block define named options in table

12    po::options_description name_desc("Options for [program]");
13    name_desc.add_options()
14        ("help", "this help message")
15        ("string", po::value<std::string>(), "pass string option to program")
16        ("int", po::value<int>()->default_value(0), "pass int option to program")
17        ;

Ex1: Printing all supported options via --help name option

$ ./program --help
Options for [program]:
--help                this help message
--string arg          pass string option to program
--int arg (=0)        pass int option to program

by following code segment

34    if (vmap.count("help"))
35    {
36        std::cout << name_desc << std::endl;
37        return 1;
38    }

Position options

Position options declare via boost::program_options::positional_options_description

Ex2: Get first unnamed argument as 'string' option

$ ./program xyz --int 5
string is xyz
int is 5

by following code segment

20    po::positional_options_description pos_desc;
21    pos_desc.add("string", -1);

store() function

The most complex part of using boost::program_options might be these part. To understand it, I recommend 'take time to read full documentation'.

28    po::store(
29            po::command_line_parser(argc, argv).
30                options(name_desc).
31                positional(pos_desc).
32                run(), vmap);