Transmits a specified character ahead of any pending data in the output buffer of the specified communications device

BOOLEAN TransmitCommChar(
  COMMHANDLE hComm,  // handle to communications device
  char cChar         // character to transmit
);

Parameters

hComm

[in] Handle to the communications device. OpenComm returns this handle.

cChar

[in] Specifies the character to be transmitted.

Return Values

Non-zero

Success.

0 (zero)

Failure. To determine the status, call GetLastRtError.

Status

E_BUSY

A write operation is already in progress.

E_DISCONNECTED

COMM channel is closed.

E_IO

A hardware error occurred.

E_LIMIT

Previous TransmitCommChar has not completed.

E_PARAM

Invalid parameter.

Remarks

This function is useful for sending an interrupt character (such as a CTRL+C) to a host system.

If the device is not transmitting, TransmitCommChar cannot be called repeatedly. Once TransmitCommChar places a character in the output buffer, the character must be transmitted before the function can be called again. If the previous character is not yet sent, TransmitCommChar returns an error.

Requirements