Creation and writing to .dat file using QFile on Windows some problem…

[freely]

I’ve outputed :
after

QFile file(QDir::toNativeSeparators(outputDir + "/" + fileName));
    file.open(QFile::ReadWrite);

QFile file(QDir::toNativeSeparators(outputDir + "/" + fileName));
    file.open(QFile::ReadWrite);

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I’ve get: file.fileName() = “(path to file + file name BUT with separators “/” and not “\” as on Windows)”
file.errorString() = “The parameter is incorrect”
file.error() = 5 ( Error in opening file ).

Why file.fileName() returns path name with “/” ( Linux like separators ) and not that of Windows “\\” or “\” ??
Still can’t open file in rw directory?
What is the problem?
Thank you for your help.