CODEWITHSUNDEEP
c++qtlogging
CowboY
CowboY

Reputation: 99

Installing message handler

I have tried to create a log file for an application by installing a message handler using qinstallMessageHandler() function. My program is as follows:

#include <QCoreApplication>
#include <QtDebug>
#include <QDir>
#include <fstream>
#include <iostream>
#include <QtCore>
#include <stdio.h>
#include <stdlib.h>

FILE *fd;

void myMessageOutput(QtMsgType type, const char *msg)
{
    QString timeStamp = QTime::currentTime().toString("hh:mm:ss:zzz");
    switch (type) {
    case QtDebugMsg:
        fprintf(fd, "[%s]", timeStamp.toStdString().c_str());
        fprintf(fd, "[Debug] %s\n", msg);
        break;
    case QtWarningMsg:
        fprintf(fd, "[%s]", timeStamp.toStdString().c_str());
        fprintf(fd, "[Warning] %s\n", msg);
        break;
    case QtCriticalMsg:
        fprintf(fd, "[%s]", timeStamp.toStdString().c_str());
        fprintf(fd, "[Critical] %s\n", msg);
        break;
    case QtFatalMsg:
        fprintf(fd, "[%s]", timeStamp.toStdString().c_str());
        fprintf(fd, "[Fatal] %s\n", msg);
        abort();
    }
}

int main(int argc, char *argv[])
{
    fd = fopen("log.txt", "a");
    qInstallMessageHandler(myMessageOutput);

    QCoreApplication a(argc, argv);



    qDebug()<<"\t Hello World!!! \n";

    return a.exec();
}

But after compiling I get the following error:

error: invalid conversion from 'void ()(QtMsgType, const char)' to 'QtMessageHandler {aka void (*)(QtMsgType, const QMessageLogContext&, const QString&)}' [-fpermissive]

Anyone here who have faced the same problem earlier?

Upvotes: 0

Views: 3179

Answers (1)

vahancho
vahancho

Reputation: 21230

It looks like you switch to Qt5 and used the message handler function signature defined in Qt4.x. You need to declare your message handler as follows:

void myMessageOutput(QtMsgType type,
                     const QMessageLogContext &context,
                     const QString &msg)
{
    [..]
}

instead.

Upvotes: 3

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