How can I solve this?

[faldzip]

char DLLfunction()
{
    QLibrary myLib("dllprog");
    typedef char* (*MyPrototype)();
    MyPrototype myFunction =
    (MyPrototype) QLibrary::resolve("dllprog", "TestDll");
    char b = myFunction();
    return b;
}

char DLLfunction()
{
    QLibrary myLib("dllprog");
    typedef char* (*MyPrototype)();
    MyPrototype myFunction =
    (MyPrototype) QLibrary::resolve("dllprog", "TestDll");
    char b = myFunction();
    return b;
}

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there is something weird in your code as define MyPrototype as raturning char* and than you do:

char b = myFunction();

char b = myFunction();

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where you are assigning returned value to one char. Is it right?