Problem uisng QTextStream

[Arshia Aghaei]

Hi , i want to use the QTextStream for stdin , stdout & stderr. Here is my code :

#include <QString>
#include <QFile>
#include <QTextStream>
 
QTextStream Output(stdout);
QTextStream Input(stdin);
QTextStream Error(stderr);
 
int main() {
    QString Path;
    Output << "Enter your path : ";
    Input >> Path;
    if(!QFile::exist(Path)) {
        Error << "Error : path does not exist." << endl;
        exit(-1);
    }
    else {
        // Some work...
    }
}

#include <QString>
#include <QFile>
#include <QTextStream>

QTextStream Output(stdout);
QTextStream Input(stdin);
QTextStream Error(stderr);

int main() {
    QString Path;
    Output << "Enter your path : ";
    Input >> Path;
    if(!QFile::exist(Path)) {
        Error << "Error : path does not exist." << endl;
        exit(-1);
    }
    else {
        // Some work...
    }
}

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The Input >> & Error << will work , but the Output << won't print anything (Without any compile error) it will cause a runtime error , why ?

[yeye_olive]

the Output << won't print anything (Without any compile error) it will cause a runtime error , why ?

What kind of runtime error?

[Arshia Aghaei]

What kind of runtime error?

Error code -1073741510.

[ChrisW67]

The signed 32 bit integer -1073741510 is 3221225786 when treated as an unsigned 32-bit integer, and 0xC000013A in hex.
That code means, STATUS_CONTROL_C_EXIT {Application Exit by CTRL+C} The application terminated as a result of a CTRL+C.
https://msdn.microsoft.com/en-us/library/cc704588.aspx

The likely reason you get no output is because the QTextStream is buffered and you have done nothing to trigger an immediate flush.
See QTextStream::flush() or the flush stream manipulator.

[Arshia Aghaei]

The signed 32 bit integer -1073741510 is 3221225786 when treated as an unsigned 32-bit integer, and 0xC000013A in hex.
That code means, STATUS_CONTROL_C_EXIT {Application Exit by CTRL+C} The application terminated as a result of a CTRL+C.
https://msdn.microsoft.com/en-us/library/cc704588.aspx

The likely reason you get no output is because the QTextStream is buffered and you have done nothing to trigger an immediate flush.
See QTextStream::flush() or the flush stream manipulator.

I don't want to use QTextStream::flush() or QTextStream::endl() , i want to get the input at the same line with the prompt ...
What should i do then ?

[jefftee]

Using QTextStream::flush() won't cause the output position to move to a new line, but it will force the output to be displayed on stdout, which I believe is what you want to occur.