Windows Mobile 6.5
A version of this page is also available for

This function configures a communications device according to specifications in a device-control block (DCB) structure.

The function reinitializes hardware and control settings, but does not empty output or input queues.

BOOL SetCommState(
  HANDLE hFile,


[in] Handle to the communications device returned by the CreateFile function.


[in] Long pointer to a DCB structure containing the configuration information for the specified communications device.

Nonzero indicates success. Zero indicates failure. To obtain extended error information, call the GetLastError function.

The SetCommState function uses a DCB structure to specify the desired configuration. The GetCommState function returns the current configuration.

To set only a few members of the DCB structure, modify a DCB structure that has been filled in by a call to GetCommState. This ensures that other members of the DCB structure have appropriate values.

The SetCommState function fails if the XonChar member of the DCB structure is equal to the XoffChar member.

Windows Embedded CEWindows CE 1.0 and later
Windows MobileWindows Mobile Version 5.0 and later

Community Additions