ClearCommError function (winbase.h)

Article
10/13/2021

Retrieves information about a communications error and reports the current status of a communications device. The function is called when a communications error occurs, and it clears the device's error flag to enable additional input and output (I/O) operations.

Syntax

BOOL ClearCommError(
  [in]            HANDLE    hFile,
  [out, optional] LPDWORD   lpErrors,
  [out, optional] LPCOMSTAT lpStat
);

Parameters

[in] hFile

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

[out, optional] lpErrors

A pointer to a variable that receives a mask indicating the type of error. This parameter can be one or more of the following values.

Value	Meaning
CE_BREAK 0x0010	The hardware detected a break condition.
CE_FRAME 0x0008	The hardware detected a framing error.
CE_OVERRUN 0x0002	A character-buffer overrun has occurred. The next character is lost.
CE_RXOVER 0x0001	An input buffer overflow has occurred. There is either no room in the input buffer, or a character was received after the end-of-file (EOF) character.
CE_RXPARITY 0x0004	The hardware detected a parity error.

The following values are not supported:

[out, optional] lpStat

A pointer to a COMSTAT structure in which the device's status information is returned. If this parameter is NULL, no status information is returned.

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.

Remarks

If a communications port has been set up with a TRUE value for the fAbortOnError member of the setup DCB structure, the communications software will terminate all read and write operations on the communications port when a communications error occurs. No new read or write operations will be accepted until the application acknowledges the communications error by calling the ClearCommError function.

The ClearCommError function fills the status buffer pointed to by the lpStat parameter with the current status of the communications device specified by the hFile parameter.

Requirements

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