Thank you for your answer.

Unfortnatelly, Your code fails in the same way as mine.

HEAP[visu000.exe]: Invalid Address specified to RtlValidateHeap( 003D0000, 00BE7260 )
Windows has triggered a breakpoint in visu000.exe.

This may be due to a corruption of the heap, and indicates a bug in visu000.exe or any of the DLLs it has loaded.

The output window may have more diagnostic information
The program '[1532] visu000.exe: Native' has exited with code 0 (0x0).


My code can read the value . The string data contains "Some value" as expected. But when the QString "data" is about to be deleted and the destructor is called the program crashes due to heap corruption.