Add Application to Startup (Registry) - c++

Question

I'm trying to add my software to registry, I have found some pieces of the codes I can use but not full working code C/C++ is new to me and can't create it on my own. But here is the basic idea: Check if reg key set if not create it.
I was able to get my program location using this code:
TCHAR szPath[MAX_PATH];
GetModuleFileName(NULL,szPath,MAX_PATH);
And was able to create the key with: (Not sure if it's the right way)
HKEY newValue;
RegOpenKey(HKEY_CURRENT_USER,"Software\\Microsoft\\Windows\\CurrentVersion\\Run",&newValue);
RegSetValueEx(newValue,"myprogram",0,REG_SZ,(LPBYTE)szPath,sizeof(szPath));
RegCloseKey(newValue);
return 0;
What is missing, A small check if the key isn't already there...
Thank you!

Answer 1

Here's some code that likely does what you want. Call RegisterProgram for your EXE to self-register itself for automatically being started when the user logs in. This function calls GetModuleFileName and then invokes another helper function called RegisterMyProgramForStartup that does the writing to the registry.
Call IsMyProgramRegisteredForStartup(L"My_Program") to detect if the registration actually exists and appears valid.
One quick note. The performance impact of checking to see if the key exists before actually writing it out again is negligible. You could just call RegisterProgram blindly and it will overwrite the key if it already exists. Detecting if the registration exists is useful for initializing your UI checkbox that enables or disables auto-start. (You are giving your users a choice, right? Because I hate apps that automatically install themselves to run automatically without giving me a choice.)
BOOL IsMyProgramRegisteredForStartup(PCWSTR pszAppName)
{
HKEY hKey = NULL;
LONG lResult = 0;
BOOL fSuccess = TRUE;
DWORD dwRegType = REG_SZ;
wchar_t szPathToExe[MAX_PATH] = {};
DWORD dwSize = sizeof(szPathToExe);
lResult = RegOpenKeyExW(HKEY_CURRENT_USER, L"Software\\Microsoft\\Windows\\CurrentVersion\\Run", 0, KEY_READ, &hKey);
fSuccess = (lResult == 0);
if (fSuccess)
{
lResult = RegGetValueW(hKey, NULL, pszAppName, RRF_RT_REG_SZ, &dwRegType, szPathToExe, &dwSize);
fSuccess = (lResult == 0);
}
if (fSuccess)
{
fSuccess = (wcslen(szPathToExe) > 0) ? TRUE : FALSE;
}
if (hKey != NULL)
{
RegCloseKey(hKey);
hKey = NULL;
}
return fSuccess;
}
BOOL RegisterMyProgramForStartup(PCWSTR pszAppName, PCWSTR pathToExe, PCWSTR args)
{
HKEY hKey = NULL;
LONG lResult = 0;
BOOL fSuccess = TRUE;
DWORD dwSize;
const size_t count = MAX_PATH*2;
wchar_t szValue[count] = {};
wcscpy_s(szValue, count, L"\"");
wcscat_s(szValue, count, pathToExe);
wcscat_s(szValue, count, L"\" ");
if (args != NULL)
{
// caller should make sure "args" is quoted if any single argument has a space
// e.g. (L"-name \"Mark Voidale\"");
wcscat_s(szValue, count, args);
}
lResult = RegCreateKeyExW(HKEY_CURRENT_USER, L"Software\\Microsoft\\Windows\\CurrentVersion\\Run", 0, NULL, 0, (KEY_WRITE | KEY_READ), NULL, &hKey, NULL);
fSuccess = (lResult == 0);
if (fSuccess)
{
dwSize = (wcslen(szValue)+1)*2;
lResult = RegSetValueExW(hKey, pszAppName, 0, REG_SZ, (BYTE*)szValue, dwSize);
fSuccess = (lResult == 0);
}
if (hKey != NULL)
{
RegCloseKey(hKey);
hKey = NULL;
}
return fSuccess;
}
void RegisterProgram()
{
wchar_t szPathToExe[MAX_PATH];
GetModuleFileNameW(NULL, szPathToExe, MAX_PATH);
RegisterMyProgramForStartup(L"My_Program", szPathToExe, L"-foobar");
}
int _tmain(int argc, _TCHAR* argv[])
{
RegisterProgram();
IsMyProgramRegisteredForStartup(L"My_Program");
return 0;
}

Answer 2

To check whether or not the value exists, call RegQueryValueEx.
LONG retval = RegQueryValueEx(hKey, "myprogram", NULL, NULL, NULL, NULL);
Note that what you called newValue is actually a key rather than a value. To avoid confusion you should name it such. I used the name hKey.
Then to check whether or not the value exists, compare retval against ERROR_SUCCESS as described in the documentation.
The other problem with your code is that there is absolutely no error checking. I'll leave that to you to address.

Answer 3

You forget to write an argument about security access