Enum question

  • Thread starter Thread starter Mario
  • Start date Start date
M

Mario

Hi,

I am having problems passing a correct argument that was using enum.
Hopefully someone can she some light.


// C++ enum from header file for the driver
typedef enum{
Port_A,
Port_B,
Port_C,
Port_D,
} G_PORTS;

//driver method signature
INT8 GetPortState(PORTHANDLE phandle, G_PORTS port, UINT32 signal)


//C# translation of the enum
public enum G_PORTS
{
Port_A,
Port_B,
Port_C,
Port_D
}

//C# P/Invoke
[DllImport("mylib.dll")]
public static extern UInt16 GetPortState(IntPtr phandle, G_PORTS port,
UINT32 signal);

//first implementation of the method call in application
SignalRead = GetPortState(phandle, G_PORTS.Port_D, 0x10000000);

After making the method call...I was not getting what I expected and I
stepped through the code to the driver. I found out that that
arguments that I passed as G_PORTS.Port_D was passed to the driver as
G_PORTS.Port_A. Could someone explain why is so? Thanks.

-- mario
 
Why is your return UInt16 when the driver returns an INT8. Based on the
name, I would think an INT8 was 8-bits.

Also, what is sizeof(G_PORTS)? Probably 32, but It would be important to
know.
 
Hi,

You are probably right in that INT8 is an 8-bits integer, and that I
err in that it should have been INT16. That is the closest thing that
C# has to an 8-bit integer or could byte be used in this case? As far
as the size, I get 0x04 when I run sizeof(G_PORTS) so that is 32-bits.
I am still baffled why the driver has the input of Port A regardless of
what arguments I used when calling the method. Again, thanks for your
input.

-- mario



Why is your return UInt16 when the driver returns an INT8. Based on the
name, I would think an INT8 was 8-bits.

Also, what is sizeof(G_PORTS)? Probably 32, but It would be important to
know.


Mario said:
Hi,

I am having problems passing a correct argument that was using enum.
Hopefully someone can she some light.


// C++ enum from header file for the driver
typedef enum{
Port_A,
Port_B,
Port_C,
Port_D,
} G_PORTS;

//driver method signature
INT8 GetPortState(PORTHANDLE phandle, G_PORTS port, UINT32 signal)


//C# translation of the enum
public enum G_PORTS
{
Port_A,
Port_B,
Port_C,
Port_D
}

//C# P/Invoke
[DllImport("mylib.dll")]
public static extern UInt16 GetPortState(IntPtr phandle, G_PORTS port,
UINT32 signal);

//first implementation of the method call in application
SignalRead = GetPortState(phandle, G_PORTS.Port_D, 0x10000000);

After making the method call...I was not getting what I expected and I
stepped through the code to the driver. I found out that that
arguments that I passed as G_PORTS.Port_D was passed to the driver as
G_PORTS.Port_A. Could someone explain why is so? Thanks.

-- mario
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