nf-winbase-opencommport.md

UID	title	description	helpviewer_keywords	old-location	tech.root	ms.assetid	ms.date	ms.keywords	req.header	req.include-header	req.target-type	req.target-min-winverclnt	req.target-min-winversvr	req.kmdf-ver	req.umdf-ver	req.ddi-compliance	req.unicode-ansi	req.idl	req.max-support	req.namespace	req.assembly	req.type-library	req.lib	req.dll	req.irql	targetos	req.typenames	req.redist	ms.custom	f1_keywords	dev_langs	topic_type	api_type	api_location	api_name
NF:winbase.OpenCommPort	OpenCommPort function (winbase.h)	Attempts to open a communication device.	FILE_FLAG_OVERLAPPED OpenCommPort OpenCommPort function base.opencommport winbase/OpenCommPort	base\opencommport.htm	base	D96D3F6D-2158-4E6A-84A8-DC3BAE9624FA	12/05/2018	FILE_FLAG_OVERLAPPED, OpenCommPort, OpenCommPort function, base.opencommport, winbase/OpenCommPort	winbase.h	Windows.h	Windows	Windows 10, version 1709 [desktop apps \| UWP apps]	Windows Server, version 1709 [desktop apps \| UWP apps]										OneCore.lib	KernelBase.dll		Windows			19H1	OpenCommPort winbase/OpenCommPort	c++	APIRef kbSyntax	DllExport	KernelBase.dll API-MS-Win-Core-comm-l1-1-0.dll API-MS-Win-DownLevel-Kernel32-l1-1-0.dll MinKernelBase.dll	OpenCommPort

OpenCommPort function

-description

Attempts to open a communication device.

-parameters

-param uPortNumber [in]

A one-based port number for the communication device to open.

-param dwDesiredAccess [in]

The requested access to the device.

For more information about requested access, see CreateFile and Creating and Opening Files.

-param dwFlagsAndAttributes [in]

The requested flags and attributes to the device.

Note  

For this function, only values of FILE_FLAG_OVERLAPPED or 0x0 are expected for this parameter.

 

Value	Meaning
FILE_FLAG_OVERLAPPED 0x40000000	The file or device is being opened or created for asynchronous I/O.

-returns

If the function succeeds, the function returns a valid HANDLE. Use CloseHandle to close that handle.

If an error occurs, the function returns INVALID_HANDLE_VALUE.

-remarks

The uPortNumber parameter accepts one-based values. A value of 1 for uPortNumber causes this function to attempt to open COM1.

To support UWP, link against WindowsApp.lib.

-see-also

CloseHandle

CreateFile

Creating and Opening Files