maintenancetool --checkupdates flag returns nothing

[ce_nort]

The maintenance tool that is bundled with online installers for Qt applications can supposedly be run headlessly with a "--checkupdates" flag that returns update information if available (see http://stackoverflow.com/questions/3...rk-auto-update ). Unfortunately I cannot get this command to actually return anything, even when there is a known update available. I can start the maintenancetool from the command line and the update is visible, but trying to use the --checkupdates flag produces nothing.

QProcess update;
update.setWorkingDirectory(QDir::currentPath());
update.start("maintenancetool --checkupdates");
 
// Wait until the maintenancetool is finished
update.waitForFinished();
 
// Read the output
QByteArray data = update.readAllStandardOutput();

QProcess update;
update.setWorkingDirectory(QDir::currentPath());
update.start("maintenancetool --checkupdates");

// Wait until the maintenancetool is finished
update.waitForFinished();

// Read the output
QByteArray data = update.readAllStandardOutput();

To copy to clipboard, switch view to plain text mode 

I can get this code to open the maintenancetool if I remove the --checkupdates flag, but data is always empty even if there is an update. If I try and run the process in the command line it also produces nothing, so I don't think it's a problem with the code. Any ideas? There doesn't seem to be a lot of information out there about this.