Attempting Windows deployment - .exe file not opening with no error messages - windows

Question

I have been attempting to deploy my app to windows (a laptop without QT installed) and I am assuming I have a dependency issue, but I am getting no error messages.
Currently using: C:\Qt\5.12.6\mingw73_64
My app runs fine in QtCreator, and I have used windeployqt (with adding the qmldir as well), which works fine initially. However, I change my C:\Qt folder to C:\QtHidden (I read somewhere that this imitates not having QT installed) and my .exe file does not load. I can click on it, but no error message comes up, my mouse cursor changes to a loading cursor for a few moments, and then nothing happens. Does anyone know of a way I can log what is happening so I can try to fix it?
I also tried following https://wiki.qt.io/Deploy_an_Application_on_Windows 'initial deployment' instructions where I put every .dll file from /bin, and every folder from plugins and qml. The same no error and no opening problem occurs and I'm not sure what else I can do.
Any ideas?
Thanks

Answer 1

Implement custom message logger. I used this code once (this one is in my actuall app and pretty generic). It can log QML errors too:
#include <QDateTime>
#include <QStandardPaths>
#include <QMessageBox>
#include <QDir>
#include <QDebug>
#include <QThread>
#include <QTextStream>
#include <iostream>
QUrl logFileUrl;
bool logToFile=true;
int appLogLevel=3;
void logger(QtMsgType type, const QMessageLogContext &context, const QString &msg){
bool writeLogLine = false;
QString line;
QString msgType;
QString time = QDateTime::currentDateTime().toString("yyyy.MM.dd hh:mm:ss.zzz");
switch (type) {
case QtInfoMsg:{
msgType = "Info";
break;
}
case QtDebugMsg:{
msgType = "Debug";
break;
}
case QtWarningMsg:{
msgType = "Warning";
break;
}
case QtCriticalMsg:{
msgType = "Critical";
break;
}
case QtFatalMsg:{
msgType = "Fatal";
abort();
}
}
line = QString("[%1] <%2> %3 (%4) | %5:%6 (%7) '%8'")
.arg(time)
.arg(static_cast<int>(reinterpret_cast<intptr_t>(QThread::currentThreadId())))
.arg(msgType)
.arg(context.category)
.arg(context.file)
.arg(context.line)
.arg(context.function)
.arg(msg);
if (!logToFile){
writeLogLine = false;
std::cout << line.toStdString() << std::endl;
} else {
switch (appLogLevel){
case 0:{
writeLogLine = false;
break;
}
case 1:{
if (type == QtFatalMsg)
writeLogLine = true;
break;
}
case 2:{
if (type == QtCriticalMsg || type == QtFatalMsg)
writeLogLine = true;
break;
}
case 3:{
if (type != QtInfoMsg && type != QtDebugMsg)
writeLogLine = true;
break;
}
case 4:{
if (type != QtDebugMsg)
writeLogLine = true;
break;
}
case 5:{
writeLogLine = true;
break;
}
}
}
if (writeLogLine){
QFile logFile(logFileUrl.toLocalFile());
if (logFile.open(QIODevice::WriteOnly | QIODevice::Append)) {
QTextStream ts(&logFile);
ts << line << endl;
logFile.close();
} else {
QMessageBox msgBox;
msgBox.setWindowTitle("WARNING");
msgBox.setIcon(QMessageBox::Warning);
msgBox.setText(logFile.errorString());
msgBox.setWindowFlags(Qt::Dialog | Qt::CustomizeWindowHint | Qt::WindowTitleHint | Qt::WindowCloseButtonHint);
msgBox.exec();
}
}
}
And the installer it using qInstallMessageHandler:
qInstallMessageHandler(logger);
Check documentation here https://doc.qt.io/qt-5/qtglobal.html#qInstallMessageHandler
P.S. - this code also displays all message in your QtCreator instance when running from there.