INT32S DRV_ReadPortByte ( PTR_T DeviceHandle, PT_ReadPortByte *lpReadPortByte );
On the device indicated by the DeviceHandle, it reads a byte of status from a system I/O port. The port specifies the absolute I/O address, which is valid only within the range of space allocated by the system.
Some parameters, such as specified I/O port address (port) and read back status (ByteData), are stored in the PT_ReadPortByte structure pointed by the lpReadPortByte.
| Name | Direction | Range | Description |
| DeviceHandle | input | default | The pointer retrieved from the DRV_DeviceOpen which specifies the target device. |
| lpReadPortByte | input / output | default | The pointer to indicate the user-prepared structure PT_ReadPortByte that stores specified I/O port address (INT16U port) and read back status (INT16U *ByteData). |
| 1. 0 | Successful. |
| 2. InvalidDeviceHandle | The DeviceHandle is NULL. |
| 3.Other value | Please reference ErrorCodes |