Question

Possible Duplicate:
Char array gives error when initializing

I want to insert an environment variable in the windows registry, so i tied the following C++ code :

string appDataPath = getenv("appdata");

    HKEY hkey;
    char value[] = appDataPath.c_str();

    RegOpenKeyEx(HKEY_CURRENT_USER, "Software\\Microsoft\\Windows\\Currentversion\\Run", 0, KEY_SET_VALUE, &hkey);
    RegSetValueEx (hkey, "MyProgram", 0, REG_SZ, (LPBYTE) value, strlen(value) + 1);
    RegCloseKey(hkey);

The codeblock debug output tell me : error: initializer fails to determine size of 'value'
I think it’s because the compilator need to know the size of my variable before compiling, however i don’t know how to fix that…

Thanks !

Answer 1

Use

const char * value = appDataPath.c_str();

(Read the < string > reference to find the return type of c_str(), it will tell you that it is indeed const char *.)

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Regarding your question of how to concatenate two strings:

Do that with C++ strings rather than with char *s and convert them later:

string newstring = appDataPath;
newstring.append("some text");
const char * value = newstring.c_str();