What parameter parser libraries are there for C++?

Question

I'd like to pass parameters to my C++ program in the following manner:

./myprog --setting=value

Are there any libraries which will help me to do this easily?

See also Argument-parsing helpers for C and Unix

Answer 1

I find it easier to use ezOptionParser. It's also a single header file, does not depend on anything but STL, works for Windows and Linux (very likely other platforms too), has no learning curve thanks to the examples, has features other libraries don't (like file import/export with comments, arbitrary option names with delimiters, auto usage formatting, etc), and is LGPL licensed.

Answer 2

Qt 5.2 comes with a command line parser API.

Small example:

#include <QCoreApplication>
#include <QCommandLineParser>
#include <QDebug>

int main(int argc, char **argv)
{
  QCoreApplication app(argc, argv);
  app.setApplicationName("ToolX");
  app.setApplicationVersion("1.2");

  QCommandLineParser parser;
  parser.setApplicationDescription("Tool for doing X.");
  parser.addHelpOption();
  parser.addVersionOption();
  parser.addPositionalArgument("infile",
      QCoreApplication::translate("main", "Input file."));

  QCommandLineOption verbose_opt("+",
      QCoreApplication::translate("main", "be verbose"));
  parser.addOption(verbose_opt);

  QCommandLineOption out_opt(QStringList() << "o" << "output",
      QCoreApplication::translate("main", "Output file."),
      QCoreApplication::translate("main", "filename"), // value name
      QCoreApplication::translate("main", "out")   // default value
      );
  parser.addOption(out_opt);

  // exits on error
  parser.process(app);

  const QStringList args = parser.positionalArguments();

  qDebug() << "Input files: " << args
    << ", verbose: " << parser.isSet(verbose_opt)
    << ", output: " << parser.value(out_opt)
    << '\n';
  return 0;
}

Example output

The automatically generated help screen:

$ ./qtopt -h
Usage: ./qtopt [options] infile
Tool for doing X.

Options:
  -h, --help               Displays this help.
  -v, --version            Displays version information.
  -+                       be verbose
  -o, --output   Output file.

Arguments:
  infile                   Input file.

Automatically generated version output:

$ ./qtopt -v
ToolX 1.2

Some real calls:

$ ./qtopt b1 -+ -o tmp blah.foo
Input files:  ("b1", "blah.foo") , verbose:  true , output:  "tmp"
$ ./qtopt          
Input files:  () , verbose:  false , output:  "out"

A parse error:

$ ./qtopt --hlp
Unknown option 'hlp'.
$ echo $?
1

Conclusion

If your program already use the Qt (>= 5.2) libraries, its command line parsing API is convenient enough to get the job done.

Be aware that builtin Qt options are consumed by QApplication before the option parser runs.

Answer 3

TCLAP is a really nice lightweight design and easy to use: http://tclap.sourceforge.net/

Answer 4

And there's a Google library available.

Really, command-line parsing is "solved." Just pick one.

Answer 5

argstream is quite similar to boost.program_option: it permits to bind variables to options, etc. However it does not handle options stored in a configuration file.

Answer 6

There are a couples of C++ argument parsers out there, you may want to try this one from http://clp.sourceforge.net/, very simple and convenient.