public static extern bool InitializeProcThreadAttributeList(

Declare Function InitializeProcThreadAttributeList Lib "kernel32.dll" (TODO) As TODO

        startupInfoEx.lpAttributeList = InitializeProcThreadAttributeList(attributeCount);

    private static IntPtr InitializeProcThreadAttributeList(int attributeCount)

        bool wasInitialized = InitializeProcThreadAttributeList(IntPtr.Zero, attributeCount, reserved, ref size);

        wasInitialized = InitializeProcThreadAttributeList(lpAttributeList, attributeCount, reserved, ref size);

Call InitializeProcThreadAttributeList before adding attributes. Save the result to a STARTUPINFOEX struct.

See CreateProcess and InitializeProcThreadAttributeList,UpdateProcThreadAttribute

See CreateProcess and InitializeProcThreadAttributeList/UpdateProcThreadAttribute