Registry manipulation

Hi,
I was wondering if there is a way to change some registry variables through some C code (under WIN XP).
Kind of things that a program does during installation (?)
Any help/links?

http://msdn.microsoft.com/
'n Search for registry or something...

If your going to get into windows programming, that site will be your best friend.

Example of registry manipulation on remote computer. To manipulate registry on local computer, set szRemoteComputerName to NULL.

Code:

#include <windows.h>
#include <stdio.h>

#pragma comment(lib, "advapi32.lib")
char szRegistryKey[128] = "SOFTWARE\\MyTest";

BOOL DeleteRegistryKey(char *ComputerName)
{
    BOOL bReturn = TRUE;
    HKEY hKeyRemote;    
    HKEY hKey;

    char szInputComputerName[48];
    if(ComputerName[0] != '\0')
        sprintf(szInputComputerName, "\\\\%s", ComputerName);
    else
        strcpy(szInputComputerName,"");
    if( RegConnectRegistry(szInputComputerName, HKEY_LOCAL_MACHINE, &hKeyRemote)
        != ERROR_SUCCESS)
    {
        bReturn = FALSE;
    }
    if(RegDeleteKey(hKeyRemote, szRegistryKey) != ERROR_SUCCESS)
    {
        bReturn = FALSE;
    }
    RegCloseKey(hKeyRemote); 
    return bReturn;
}

BOOL UpdateRegistry(char *ComputerName, char *ComPort, DWORD *dwRS232Timeout,DWORD *dwDebugMode, DWORD *dwServerPort, DWORD *dwLogFileSize)
{
    HKEY hKeyRemote;    
    HKEY hKey;
    LPDWORD lpdwDisp = 0;
    char szInputComputerName[48];

    BOOL bUpdateSuccessful = TRUE;
    memset(szInputComputerName, 0, sizeof szInputComputerName);
    if(ComputerName[0] != '\0')
        sprintf(szInputComputerName, "\\\\%s", ComputerName);
    else
        strcpy(szInputComputerName,"");

    if( RegConnectRegistry(szInputComputerName, HKEY_LOCAL_MACHINE, &hKeyRemote)
        != ERROR_SUCCESS)
    {
        return FALSE;
    }
    if( RegCreateKeyEx( hKeyRemote, szRegistryKey, 0L,NULL,
        REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, NULL, &hKey,lpdwDisp))
    {
        bUpdateSuccessful = FALSE;
    }
    else
    {
        if (RegSetValueEx(hKey, "ComPort", 0, REG_SZ,(LPBYTE) ComPort,(DWORD)
            lstrlen(ComPort)+1))
        {
            bUpdateSuccessful = FALSE;
        }
        if (RegSetValueEx (hKey, "RS232Timeout", 0L, REG_DWORD,(CONST BYTE*)
            &dwRS232Timeout, sizeof(DWORD)))
        {
            bUpdateSuccessful = FALSE;
        }
        if (RegSetValueEx (hKey, "DebugMode", 0L, REG_DWORD,(CONST BYTE*)
            &dwDebugMode, sizeof(DWORD)))
        {
            bUpdateSuccessful = FALSE;
        }   
        if (RegSetValueEx (hKey, "ServerPort", 0L, REG_DWORD,(CONST BYTE*)
            &dwServerPort, sizeof(DWORD)))
        {
            bUpdateSuccessful = FALSE;
        } 
        if (RegSetValueEx (hKey, "LogFileSize", 0L, REG_DWORD,(CONST BYTE*)
            &dwLogFileSize, sizeof(DWORD)))
        {
            bUpdateSuccessful = FALSE;
        } 
    }
    RegCloseKey(hKey); 
    RegCloseKey(hKeyRemote); 
    return bUpdateSuccessful;
}

BOOL ReadRegistry(char *ComputerName,char *ComPort, DWORD &dwRS232Timeout, DWORD &dwDebugMode, DWORD &dwServerPort, DWORD &dwLogFileSize)
{

    HKEY hKeyRemote, hKey;
    char szComPort[6] = {0};
    char szInputComputerName[64] = {0};
    BOOL bReturn = TRUE;
    DWORD datasize = 0;
    DWORD type = 0;
    if(ComputerName[0] != '\0')
        sprintf(szInputComputerName, "\\\\%s", ComputerName);
    else
        strcpy(szInputComputerName,"");

    if( RegConnectRegistry(szInputComputerName, HKEY_LOCAL_MACHINE, &hKeyRemote)
        != ERROR_SUCCESS)
    {
        return FALSE;
    }
    if(RegOpenKeyEx (hKeyRemote, szRegistryKey, 0, KEY_QUERY_VALUE,
        &hKey) == ERROR_SUCCESS)
    {
        datasize = sizeof (szComPort);
        if (RegQueryValueEx(hKey, "ComPort",NULL, NULL, (unsigned char *)&szComPort,
            (unsigned long *)&datasize) != ERROR_SUCCESS)
            bReturn = FALSE;
        else 
            strcpy(ComPort , szComPort);
        datasize = sizeof(DWORD);
        if(RegQueryValueEx(hKey, "RS232Timeout",  0L, &type, (LPBYTE)&dwRS232Timeout,
            &datasize) != ERROR_SUCCESS)
        {
            dwRS232Timeout  = 0;
            bReturn = FALSE;
        }
        if(RegQueryValueEx(hKey, "DebugMode",  0L, &type, (LPBYTE)&dwDebugMode,
            &datasize) != ERROR_SUCCESS)
        {
            dwDebugMode = 0;  
            bReturn = FALSE; 
        }
        if(RegQueryValueEx(hKey, "ServerPort",  0L, &type, (LPBYTE)&dwServerPort,
            &datasize) != ERROR_SUCCESS)
        {
            dwServerPort = 0;  
            bReturn = FALSE; 
        }
        if(RegQueryValueEx(hKey, "LogFileSize",  0L, &type, (LPBYTE)&dwLogFileSize,
            &datasize) != ERROR_SUCCESS)
        {
            dwLogFileSize = 0;
            bReturn = FALSE; 
        }
        RegCloseKey(hKey);     
        RegCloseKey(hKeyRemote);
    }
    else bReturn = FALSE;
    return bReturn;
}

int main(void)
{
    char szRemoteComputerName[] = {"NET0"};
    char szComPort[6] = {0};
    DWORD dwRs232Timeout = 0; 
    DWORD dwServerPort = 0;
    DWORD dwLogFileSize = 0;
    DWORD dwDebugMode = 0 ;
    if(UpdateRegistry(szRemoteComputerName, "COM4", (DWORD *)4000, (DWORD *)1,(DWORD *)4390,(DWORD *)100 ) == TRUE)
        printf("update successful\n");
    else
        printf("update failed\n");

    if(  ReadRegistry(szRemoteComputerName,szComPort, dwRs232Timeout, dwDebugMode,dwServerPort, dwLogFileSize) == FALSE)
        printf("Read failed\n");
    else
        printf("Read successful,  Comport = %s RS232Timeout = %d DebugMode = %d  ServerPort = %d LogSize = %d\n", szComPort,dwRs232Timeout, dwDebugMode,dwServerPort, dwLogFileSize );
    if(DeleteRegistryKey(szRemoteComputerName) == TRUE)
        printf("deletion successful\n");
    else
        printf("deletion failed\n");
    return 0;
}

The following has also been useful.

Code:

http://hawk-ware.awardspace.com/tutorials/cppreg.html

Thanks for the answers..