QImageReader imgReader;
 imgReader.setFileName("filename");
QImage *img = new QImage();
QFuture<QImage> future = QtConcurrent::run(imgReader, &QImageReader::read);
 *img = future.result();

../Qt/4.4.1/include/QtGui/../../src/gui/image/qimagereader.h: In constructor `QtConcurrent::StoredMemberFunctionCall0<T, Class>::StoredMemberFunctionCall0(T (Class::*)(), const Class&) [with T = QImage, Class = QImageReader]':

../Qt/4.4.1/include/QtCore/../../src/corelib/concurrent/qtconcurrentrun.h:169:   instantiated from `QFuture<T> QtConcurrent::run(const Class&, T (Class::*)()) [with T = QImage, Class = QImageReader]'

image.cpp:53:   instantiated from here

../Qt/4.4.1/include/QtGui/../../src/gui/image/qimagereader.h:133: error: `QImageReader::QImageReader(const QImageReader&)' is private

../Qt/4.4.1/include/QtCore/../../src/corelib/concurrent/qtconcurrentstoredfunctioncall.h:120: error: within this context

mingw32-make[1]: *** [debug/image.o] Error 1

Видимо такая бяка происходит при вызове из конструктора.

QFuture<T> QtConcurrent::run ( Function function, ... )
Runs function in a separate thread. The thread is taken from the global QThreadPool. Note that the function may not run immediately; the function will only be run when a thread is available.

T is the same type as the return value of function. Non-void return values can be accessed via the QFuture::result() function.

Note that the QFuture returned by QtConcurrent::run() does not support canceling, pausing, or progress reporting. The QFuture returned can only be used to query for the running/finished status and the return value of the function.