c++ RegSetValueEx sets only one char value in registry

Question

I'm casting (char * ) on data and i'm getting only one char value in the registry. if i don't use the casting msvc 2010 tells me that the argument type LPCTSTR is incompatible with const char *.

can someone help me?

HKEY hKey;
LPCTSTR sk = TEXT("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run");

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

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

LPCTSTR value = TEXT("SomeKey");
LPCTSTR data = L"TestData\0";

LONG setRes = RegSetValueEx (hKey, value, 0, REG_SZ, (LPBYTE)data, strlen(data)+1);

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

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

Solution 1

strlen(data) is probably returning a value of 1, as strlen expects a char* and L"TestData\0" is wide. Use TEXT("TestData\0") and call _tcslen(data).
Note that RegSetValueEx expects the sizeof the data, so use _tcslen(data) * sizeof(TCHAR)

Solution 2

replace the L"TestData" by _T("TestData"); and strlen(data)+1 by tcslen(data) * sizeof(TCHAR));

so your code looks like this :

LPCTSTR value = TEXT("SomeKey");
LPCTSTR data = TEXT("TestData");

LONG setRes = RegSetValueEx(hKey, value, 0, REG_SZ, (LPBYTE)data, _tcslen(data) * sizeof(TCHAR));

Solution 3

Where are you casting data?

Either way, it looks like you may be working with wide characters, but you seem to be using "plain old" strlen - instead of wcslen or some other function intended to work with wide-character strings.

Comments

[zenzelezz]

Looks like a better explanation/suggestion than mine :)

[Tom]

when i try to use this, for example LPCTSTR data = TEXT("ThisIsTheValueIWant\0"); then i get in registry only "ThisIsTheV" what should i do?

[Joel Rondeau]

Answer modified to take this into account.