A simple getopt wrapper for C++ in one header file.
#include "flags.hh"
// Declare a non-boolean flag
template <typename T>
void Var(T & var, char shortFlag, std::string longFlag, T defaultValue, std::string description, std::string descriptionGroup = "");
// Declare a boolean flag
void Bool(bool & var, char shortFlag, std::string longFlag, std::string description, std::string descriptionGroup = "");
When setting through command-line flags:
Flags::Var(): the flag should be followed with an argument which is stored in the referenced variable var.
Flags::Bool(): if the flag is presented, the referenced boolean variable var is set to true; otherwise, it's set to false. The command-line flag should NOT be followed with an argument.
reference to the variable to store value.
short option of the declared variable; one character; this shouldn't contain the leading dash -.
long option of the declared variable; this shouldn't contain the leading double dashes --.
the default value for the variable (non-boolean only).
description of the option for the help message; if this is too long, it will be wrapped.
if not empty, it is used to organize options into groups.
bool Parse(int argc, char ** argv);
void PrintHelp(char * argv0, std::ostream & to = std::cout);
/* Song Gao <song@gao.io> | June 2015 */
#include "Flags.hh"
#include <cstdint>
#include <iostream>
int main(int argc, char ** argv) {
uint64_t var1;
uint32_t var2;
int32_t var3;
std::string str;
bool b, help;
Flags flags;
flags.Var(var1, 'a', "var1", uint64_t(64), "This is var1!");
flags.Var(var2, 'b', "var2", uint32_t(32), "var2 haahahahaha...");
flags.Var(var3, 'c', "var3", int32_t(42), "var3 is signed!", "Group 1");
flags.Var(str, 's', "str", std::string("Hello World!"), "This is a string, and the description is too long to fit in one line and has to be wrapped blah blah blah blah...", "Group 1");
flags.Bool(b, 'd', "bool", "this is a bool variable", "Group 2");
flags.Bool(help, 'h', "help", "show this help and exit", "Group 3");
if (!flags.Parse(argc, argv)) {
flags.PrintHelp(argv[0]);
return 1;
} else if (help) {
flags.PrintHelp(argv[0]);
return 0;
}
std::cout << "var1: " << var1 << std::endl;
std::cout << "var2: " << var2 << std::endl;
std::cout << "var3: " << var3 << std::endl;
std::cout << "str: " << str << std::endl;
std::cout << "b: " << (b ? "set" : "unset") << std::endl;
return 0;
}$ ./example -h
Usage: ./example [options]
-a --var1 [default: 64]
This is var1!
-b --var2 [default: 32]
var2 haahahahaha...
Group 1:
-c --var3 [default: 42]
var3 is signed!
-s --str [default: Hello World!]
This is a string, and the description is too long to fit in one line and h
as to be wrapped blah blah blah blah...
Group 2:
-d --bool [default: (unset)]
this is a bool variable
Group 3:
-h --help [default: (unset)]
show this help and exit
$ ./example -a1 --var2 2 -c 3 -s 'multi word string' --bool
var1: 1
var2: 2
var3: 3
str: multi word string
b: set
$ ./example
var1: 64
var2: 32
var3: 42
str: Hello World!
b: unset