Writing string (REG_SZ) values to the registry in C++

Question

I\'ve got most of the code for writing a value to the windows registry, however when I change the path to a dummy key and value that I\'ve set up for testing it fails. My code

Answer 1

For UNICODE environment:

//Writing to registry
HKEY hKey;
LPCTSTR sk = TEXT("SOFTWARE\\Microsoft\\Windows");

LONG openRes = RegOpenKeyEx(HKEY_LOCAL_MACHINE, sk, 0, KEY_ALL_ACCESS, &hKey);

if (openRes == ERROR_SUCCESS) {
    printf("Success opening key.");
}
else {
    printf("Error opening key.");
}

LPCTSTR value = TEXT("Sample");
WCHAR path[80] = TEXT("C:\\samples\\app.exe");

LONG setRes = RegSetValueEx(hKey, value, 0, REG_SZ, (LPBYTE)path, sizeof(path));

if (setRes == ERROR_SUCCESS) {
    printf("Success writing to Registry.");
}
else {
    printf("Error writing to Registry.");
}

LONG closeOut = RegCloseKey(hKey);

if (closeOut == ERROR_SUCCESS) {
    printf("Success closing key.");
}
else {
    printf("Error closing key.");
}

Answer 2

HKEY OpenKey(HKEY hRootKey, char* strKey)
{
  HKEY hKey;
  LONG nError = RegOpenKeyEx(hRootKey, strKey, NULL, KEY_ALL_ACCESS, &hKey);

  if (nError==ERROR_FILE_NOT_FOUND)
  {
    cout << "Creating registry key: " << strKey << endl;
    nError = RegCreateKeyEx(hRootKey, strKey, NULL, NULL,     REG_OPTION_NON_VOLATILE,KEY_ALL_ACCESS,NULL, &hKey, NULL);
  }

  if (nError)
    cout << "Error: " << nError << " Could not find or create " <<      strKey << endl;

  return hKey;
}

void SetintVal(HKEY hKey, LPCTSTR lpValue, DWORD data)
{
  LONG nError = RegSetValueEx(hKey, lpValue, NULL, REG_DWORD,   (LPBYTE)&data, sizeof(DWORD));

  if (nError)
      cout << "Error: " << nError << " Could not set registry value: " << (char*)lpValue << endl;
}

DWORD GetintVal(HKEY hKey, LPCTSTR lpValue)
{
  DWORD data;
  DWORD size = sizeof(data);
  DWORD type = REG_DWORD;
  LONG nError = RegQueryValueEx(hKey, lpValue, NULL, &type, (LPBYTE)&data, &size);

  if (nError==ERROR_FILE_NOT_FOUND)
     data = 0; 
  SetVal() is called.
  else if (nError)
    cout << "Error: " << nError << " Could not get registry value " << (char*)lpValue << endl;

  return data;
}

BOOL SetcharVal(HKEY Key,char* subkey,char* StringName,char* Stringdata)
{
  HKEY hKey = OpenKey(Key,subkey);

  LONG openRes = RegOpenKeyEx(Key, subkey, 0, KEY_ALL_ACCESS , &hKey);

  if (openRes==ERROR_SUCCESS) {

  } else {
    printf("Error opening key.");
  }

  LONG setRes = RegSetValueEx (hKey, StringName, 0, REG_SZ, (LPBYTE)Stringdata, strlen(Stringdata)+1);

  if (setRes == ERROR_SUCCESS) {

  } else {
    printf("Error writing to Registry.");
  }

  LONG closeOut = RegCloseKey(hKey);

  if (closeOut == ERROR_SUCCESS) {

  } else {
    printf("Error closing key.");
  }

}

char* GetCharVal(HKEY Key,char* subkey,char* StringName)
{
  DWORD dwType = REG_SZ;
  HKEY hKey = 0;
  char value[1024];
  DWORD value_length = 1024;
  RegOpenKey(HKEY_LOCAL_MACHINE,subkey,&hKey);
  RegQueryValueEx(hKey, StringName, NULL, &dwType, (LPBYTE)&value,     &value_length);
  RegCloseKey(hKey);
  return value;
}

I am using this code.

Answer 3

I feel silly. The solution is that need to properly escape the slash in the string as follows:

LPCTSTR sk = TEXT("SOFTWARE\\TestSoftware");

Hopefully someone finds this useful...