Command line parser for Qt4

Question

I am looking for a command line parser for Qt4.

I did a small google search, and found this: http://www.froglogic.com/pg?id=PublicationsFreeware&category=getopt however it lacks support for "--enable-foo" and "--disable-foo" switches. Besides that, it looks like a real winner.

EDIT:

It seems Frologic removed this. So the best options I see are using Boost (which is not API nor ABI stable) or forking the support for kdelibs. Yay...

Answer 1

QCoreApplication's constructors require (int &argc, char **argv) (and QApplication inherits from QCoreApplication). As the documentation states, it is highly recommended that

Since QApplication also deals with common command line arguments, it is usually a good idea to create it before any interpretation or modification of argv is done in the application itself.

And if you're letting Qt get the first pass at handling arguments anyways, it would also be a good idea to use QStringList QCoreApplication::arguments() instead of walking through argv; QApplication may remove some of the arguments that it has taken for its own use.

This doesn't lend itself to being very compatible with other argument-parsing libraries...

However, kdelibs does come with a nice argument parser, KCmdLineArgs. It is LGPL and can be used without KApplication if you really want (call KCmdLineArgs::init).

KCmdLineOptions options;
options.add("enable-foo", ki18n("enables foo"));
options.add("nodisable-foo", ki18n("disables foo"));
// double negatives are confusing, but this makes disable-foo enabled by default

KCmdLineArgs::addCmdLineOptions(options);
KApplication app;
KCmdLineArgs *args = KCmdLineArgs::parsedArgs();

if (args->isSet("enable-foo") && !args->isSet("disable-foo"))
    cout << "foo enabled" << endl;
else
    cout << "foo disabled" << endl;

Untested (who ever tests what they post on S.O.?).

Answer 2

Since Qt 5.2 you can finally find a solution in QtCore itself: I contributed QCommandLineParser there.

Answer 3

This is more or less the same answer as ephemient, but with a simple regexp to help parse the args. (This way could be useful if you only need a handful of args)

Run with this:

./QArgTest --pid=45 --enable-foo

And the code:

int main(int argc, char *argv[]) {
    QApplication app(argc, argv, false);
    qDebug() << "QApp arg test app"; 

    QStringList args = app.arguments();

    int pid = 0;

    QRegExp rxArgPid("--pid=([0-9]{1,})");
    QRegExp rxArgFooEna("--enable-foo");
    QRegExp rxArgFooDis("--disable-foo");

    for (int i = 1; i < args.size(); ++i) {
        if (rxArgPid.indexIn(args.at(i)) != -1 ) {   
            pid =  rxArgPid.cap(1).toInt();
            qDebug() << i << ":" << args.at(i) << rxArgPid.cap(1) << pid;
        }
        else if (rxArgFooEna.indexIn(args.at(i)) != -1 ) {   
            qDebug() << i << ":" << args.at(i) << "Enable Foo";
        } 
        else if (rxArgFooDis.indexIn(args.at(i)) != -1 ) {   
            qDebug() << i << ":" << args.at(i) << "Disable Foo";
        } 
        else {
            qDebug() << "Uknown arg:" << args.at(i);
        }
    }
    return 0;
}

Answer 4

There is also QxtCommandOptions from http://www.libqxt.org/