QCommandLineOption cannot get option

Question

I use QCommandLineOption to parse my command line option.

this is my Arguments class:

 #include "arguments.h" #include <QDebug> /** * @brief Constructor, need to know QApplication pointer * @param app */ Arguments::Arguments(QApplication *app) { parser.setApplicationDescription("Convert html doc to pdf"); parser.addHelpOption(); parser.addVersionOption(); parser.addPositionalArgument("source", QApplication::translate("main", "Source file to copy.")); parser.addPositionalArgument("destination", QApplication::translate("main", "Destination file (ie /home/morgan/test.pdf)")); setOption(); // Process the actual command line arguments given by the user parser.process(*app); args = parser.positionalArguments(); } /** * @brief Arguments::getSource * @return QString the full path to file to be converted */ QString Arguments::getSource() { return args.isEmpty() ? QString() : args.at(0); } /** * @brief Arguments::getDest * @return QString the path to file that will be converted */ QString Arguments::getDest() { return args.isEmpty() ? QString() : args.at(1); } /** * @brief Arguments::getOrientation * @return Orientation Mode (Portrait or Landscape ?) */ QPrinter::Orientation Arguments::getOrientation() { // init orientation options values QStringList orientationOptions; orientationOptions << "portrait" << "landscape" ; // get orientation value QString orientation = parser.value("orientation").toLower(); switch (orientationOptions.indexOf(orientation)) { case 0: return QPrinter::Portrait; break; case 1: return QPrinter::Landscape; break; default: return QPrinter::Portrait; break; } } /** * @brief should print in color or not ? * @return color mode */ QPrinter::ColorMode Arguments::getColorMode() { bool gray = parser.isSet("gray"); if(gray == true) return QPrinter::GrayScale; else return QPrinter::Color; } int Arguments::getPageBegin() { QString val = parser.value("begin"); int v = val.toInt(); return v; } int Arguments::getPageEnd() { return parser.value("end").toInt(); } /** * @brief Arguments::isValidArgument * @return the app have all necesary arguments ? */ bool Arguments::isValidArgument() { if (args.size() < 2) { fprintf(stderr, "%s\n", qPrintable(QApplication::translate("main", "Error: Must specify arguments."))); parser.showHelp(1); return false; } else { return true; } } /** * @brief Add all option can be given by argument */ void Arguments::setOption() { // A String orientation mode (-o, --orientation) QCommandLineOption orientationOption(QStringList() << "o" << "orientation", QApplication::translate("main", "set orientation to Landscape or Portrait (default is Portrait)."), QApplication::translate("main", "orientation"), "Portrait"); parser.addOption(orientationOption); // print to gray mode (-g, --gray) QCommandLineOption grayOption(QStringList() << "g" << "gray", QApplication::translate("main", "should print in gray or not")); parser.addOption(grayOption); // int page start to print (-b --begin) QCommandLineOption beginOption(QStringList() << "b" << "begin", QApplication::translate("main", "number of the page where it starts to print")); parser.addOption(beginOption); QCommandLineOption endOption(QStringList() << "e" << "end", QApplication::translate("main", "number of the page where it stop to print")); parser.addOption(endOption); } 

If I use the orientation parameter (or colorMode), it works fine, but I cannot get the value of the begin parameter:

 QString val = parser.value("begin"); // return always : "" 

Usage example:

./tool http://google.com ./ --begin =5

top of page: 0
end of page: 0

./tool http://google.com ./ --begin=5

Unexpected value after '--begin'.

./tool http://google.com ./ -b 5

top of page: 0
end of page: 0

True, I do not understand why?

Answer 1

You need to indicate that it should expect value.

QCommandLineOption::QCommandLineOption : In addition, QCommandLineOption::QCommandLineOption can be set if the option expects a value.

QCommandLineOption::setValueName : Options without an assigned value have a logical behavior: either the user specifies --option or not. Parameters with the assigned value, you must set the name for the expected value for documentation on the option in the help output. An option with the names o and output and the file value name will display as -o, --output <file> .

 QCommandLineOption beginOption(QStringList() << "b" << "begin", QApplication::translate("main", "number of the page where it starts to print"), "page", "0"); 

Answer 2

The documentation for the QCommandLineOption constructor says:

QCommandLineOption::QCommandLineOption(const QStringList & names, const QString & description = QString(), const QString & valueName = QString(), const QString & defaultValue = QString())

[...]

In addition, the value Name can be set if the option expects a value. The default value for the parameter is set to defaultValue.

You need to pass valueName (the third argument to the constructor) to say that the parameter can have a value, and not just be a logical on / off parameter:

 QCommandLineOption beginOption(QStringList() << "b" << "begin", QApplication::translate("main", "number of the page where it starts to print"), "page", "0");