TransmitCommChar function (winbase.h)

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


BOOL TransmitCommChar(
  [in] HANDLE hFile,
  [in] char   cChar


[in] hFile

A handle to the communications device. The CreateFile function returns this handle.

[in] cChar

The character to be transmitted.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.


The TransmitCommChar 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 has not yet been sent, TransmitCommChar returns an error.


Requirement Value
Minimum supported client Windows XP [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 [desktop apps | UWP apps]
Target Platform Windows
Header winbase.h (include Windows.h)
Library Kernel32.lib
DLL Kernel32.dll

See also

Communications Functions

Communications Resources