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c#c++interoppinvokeintptr

Passing a const char* character string from unmanaged to managed

I have two communicating components - one managed, the other unmanaged. The managed needs to retrieve a character string from the unmanaged implementation (the same string or just a copy). I tried the following code.

// Unmanaged code
const char* GetTestName(Test* test)
{
    return test->getName();
}

// Managed wrapper
[DllImport(DllName, EntryPoint = "GetTestName")]
public static extern IntPtr GetTestName(IntPtr testObj);

// API Invocation
IntPtr testName = GetTestName(test);
string testStr = Marshal.PtrToStringAuto(testName);

But, the value of testStr is not what is expected. Does anyone know what I'm doing wrong here? Any suggestions would be really helpful.

Solution

  • You're close but you have to use PtrToStringAnsi(). Auto uses the system default which will be Unicode.