char* to QString: conversion

[abghosh]

Hi

While calling dll file from vb.net I am passing a string value to the qt dllas follows:

<DllImport("G:\Varen_CS\02_Projects\01_Softwares\highFreqTrad\test\debug\test.dll", _
               CharSet:=CharSet.Auto, _
               CallingConvention:=CallingConvention.StdCall)> _
    Private Shared Function _ZN11QtEngineDll7randIntEv(ByRef u As String) As String
    End Function

<DllImport("G:\Varen_CS\02_Projects\01_Softwares\highFreqTrad\test\debug\test.dll", _
               CharSet:=CharSet.Auto, _
               CallingConvention:=CallingConvention.StdCall)> _
    Private Shared Function _ZN11QtEngineDll7randIntEv(ByRef u As String) As String
    End Function

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Now my qtcode goes as follows:

QtEngineDll::QtEngineDll(const char* url)
{
    m = url;
}
 
const char* QtEngineDll::randInt()
{
    QByteArray d(m);
    QString result = d.data();
    QString fileName = QDir::currentPath() + "/Test.txt";
    QFile file(fileName);
    file.open(QIODevice::Append | QIODevice::Text);
    file.write(result + "\n");
    return result;
}

QtEngineDll::QtEngineDll(const char* url)
{
    m = url;
}

const char* QtEngineDll::randInt()
{
    QByteArray d(m);
    QString result = d.data();
    QString fileName = QDir::currentPath() + "/Test.txt";
    QFile file(fileName);
    file.open(QIODevice::Append | QIODevice::Text);
    file.write(result + "\n");
    return result;
}

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But the file output is something like this:

[07/03/10 - 12:03:46],	Abhijit	U‰åVSƒìpE¸‰$èT

[07/03/10 - 12:03:46],	Abhijit	U‰åVSƒìpE¸‰$èT

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Can you pls tell me what is the wrong that I am committing in the code?

Thanks in advance.