Use the RegNotifyChangeKeyValue API for Receiving Notification Messages

Windows applications generally use the registry for storing configuration information. Sometimes, it can be essential to allow users to change the registry key/value and the same needs to be reflected by the application dynamically (without restarting the application). This is where RegNotifyChangeKeyValue comes to the rescue. This API notifies the caller about changes to the contents of a particular registry key.

The following example shows a sample application that monitors a value entry named “User” under HKEY_LOCAL_MACHINEsoftwareDevX registry key. Any change is captured by the sample application and displayed on the Console. Here’s an example:

DWORD WINAPI RegNotifyProc(LPVOID x) {	DWORD  dwFilter = REG_NOTIFY_CHANGE_LAST_SET, dwType, dwSize ;char lpszUser[81];HANDLE hEvent;	HKEY   hKey;	LONG   lErrorCode;	while(1) 	{		memset(lpszUser,0,81);		dwSize = 81;		dwType = REG_SZ;	// Open a key. Change second parameter to fit your needs.		lErrorCode = RegOpenKeyEx(HKEY_LOCAL_MACHINE, "software\DevX", 0,KEY_NOTIFY | KEY_READ, &hKey);		// Create an event.		hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);		// Watch the registry key for a change of value.		lErrorCode = RegNotifyChangeKeyValue(hKey, TRUE, dwFilter, hEvent,TRUE);		// Wait for an event to occur.		WaitForSingleObject(hEvent, INFINITE);		lErrorCode = RegQueryValueEx(hKey,"User",0,&dwType,(unsigned char*)lpszUser,&dwSize);		//Add code for reading from the registry key		printf("Modified... : %s
",lpszUser);		// Close the key.		lErrorCode = RegCloseKey(hKey);		// Close the handle.		CloseHandle(hEvent);		Sleep(1); 	}	return 1; }
Share the Post:
Share on facebook
Share on twitter
Share on linkedin

Overview

The Latest

iOS app development

The Future of iOS App Development: Trends to Watch

When it launched in 2008, the Apple App Store only had 500 apps available. By the first quarter of 2022, the store had about 2.18 million iOS-exclusive apps. Average monthly app releases for the platform reached 34,000 in the first half of 2022, indicating rapid growth in iOS app development.

microsoft careers

Top Careers at Microsoft

Microsoft has gained its position as one of the top companies in the world, and Microsoft careers are flourishing. This multinational company is efficiently developing popular software and computers with other consumer electronics. It is a dream come true for so many people to acquire a high paid, high-prestige job

your company's audio

4 Areas of Your Company Where Your Audio Really Matters

Your company probably relies on audio more than you realize. Whether you’re creating a spoken text message to a colleague or giving a speech, you want your audio to shine. Otherwise, you could cause avoidable friction points and potentially hurt your brand reputation. For example, let’s say you create a