any way to catch error message from dll in a gui app?

[lvdong]

I'm using QLibrary to load a dll in a gui app, the problem is how to catch the error message in stderr from the dll.

dll.cpp
...
std::cerr << "error!" << std::endl;
...

I tried using QFile to open the stderr, but got nothing.
file.open(stderr, QIODevice::ReadOnly);
QByteArray msg = file.readAll();

Thanks!