Crash when removing a QTemporaryFile

Question

I convert QFile into FILE* to use some third-part libraries. Here is code:

QTemporaryFile pack200_file;

//Here write something into pack200_file
......

pack200_file.seek(0);
int handle_in = pack200_file.handle();
if (handle_in == -1)
{
    qCritical() << "Error reopening " << pack200_file.fileName();
    return false;
}
FILE * file_in = fdopen(handle_in, "r");
if(!file_in)
{
    qCritical() << "Error reopening " << pack200_file.fileName();
    return false;
}
QTemporaryFile qfile_out;
if(!qfile_out.open())
{
    qCritical() << "Error opening " << qfile_out.fileName();
    return false;
} 
int handle_out = qfile_out.handle();
if (handle_out == -1)
{
    qCritical() << "Error opening " << qfile_out.fileName();
    return false;
}
FILE * file_out = fdopen(handle_out, "w");
if (!file_out)
{
    qCritical() << "Error opening " << qfile_out.fileName();
    return false;
}
try
{
    unpack_200(file_in, file_out);
}
catch (std::runtime_error &err)
{
    qCritical() << "Error unpacking " << pack200_file.fileName() << " : " << err.what();
    return false;
}

//success
QString finalJarname = .....;
QFile::remove(finalJarname);
QFile::copy(qfile_out.fileName(), finalJarname);
fclose(file_in);
fclose(file_out);
qfile_out.remove(); //Here I got crash
pack200_file.remove();  
return true;

I got crash at the line qfile_out.remove();, It seems the remove operation cause it. But I got nothing from trace stack and visual studio do not mention me which code trigger the crash finally.

If I change the code into:

fclose(file_in);
fclose(file_out);
qfile_out.setAutoRemove(false);
pack200_file.setAutoRemove(false);
qfile_out.close();
pack200_file.close();
return true;

it will also crash when return ;

Then I change IDE into QtCreator, it said:

Second Chance Assertion Failed: File f:\dd\vctools\crt\crtw32\lowio\close.c , Line 47

Expression: (_osfile(fh) & FOPEN)

But I can't find the file f:\dd\vctools\crt\crtw32\lowio\close.c. How can I localize the source of the crash?

Answer 1

You closed qfile_out's file for it with fclose(). Looks like the Visual C runtime library didn't like that, hence the exception. Suggest you remove the calls to fclose... or avoid mixing Qt and non-Qt file operations.