_VCOMM_ReadComm

include vcomm.inc

VxDcall _VCOMM_ReadComm, <hPort, <OFFSET32 achBuffer>, \
    cchRequested, <OFFSET32 cchReceived>>
or      eax, eax
jz      error_handler

Reads characters from the receive queue for the specified port, and returns immediately. Uses the C calling convention. This is an asynchronous service.

• Returns TRUE if successful, FALSE otherwise. For extended error information, use _VCOMM_GetLastError.

hPort

Handle of a communications resource.

achBuffer

Address of a buffer that receives the data.

cchRequested

Number of characters to read from the receive queue.

cchReceived

Address of a 32-bit variable that receives the number of characters to read. This value is less than cchRequested if the receive queue does not contain enough characters; it is zero if a communications error occurs.

If a communications error has occurred, the service returns TRUE, but doesn't read any characters. In this case, call _VCOMM_ClearCommError.

See also _VCOMM_ClearCommError, _VCOMM_GetLastError