[SOLVED] Qt QProcess desn't work with arguments containing wildcard charecters

Issue

I want to pass an argument containing asterisk to QProcess. The
code listed below can reproduce my problem:

#include <QDebug>
#include <QProcess>

int main(int argc, char * argv[])
{
    QStringList arguments;
    arguments << "-l" << "*.cpp";
    QProcess ps;
    ps.start("ls", arguments);
    ps.waitForFinished();
    qDebug() << ps.readAll();
}

I can’t get ls -l *.cpp run as in a shell. What is the right way to make wildcard characters work for QProcess? I’m using Qt 5.15.2 coming with Debian stable.

Solution

When you run ls -l *.cpp, the expansion of * to a list of filenames is performed by your shell.
In this case, ls already receives a list of filenames.

In the case of QProcess, the process is directly executed without a shell. So there is no party involved that performs the expansion (called "globbing").

In your case, I would use QDir::entryList() to obtain the list of files and then pass the result as arguments.

Untested example code:

#include <QDebug>
#include <QProcess>
#include <QDir>

int main(int argc, char * argv[])
{
    QStringList arguments = {"-l"};

    QDir directory("."); // same as QDir()
    QStringList filters = {"*.cpp"};
    arguments << directory.entryList(filters);

    QProcess ps;
    ps.start("ls", arguments);
    ps.waitForFinished();
    qDebug() << ps.readAll();
}

Answered By – ypnos

Answer Checked By – Jay B. (BugsFixing Admin)