Use Modern C++ to Access the Windows Registry

摘要

The Windows OS exposes a series of C-interface APIs to give developers access to the registry. Some of these APIs are fairly low level and require programmers to pay attention to many details. Starting with Windows Vista, a kind of higher-level API was added to the mix: the RegGetValue function (bit.ly/2jXtfpJ). Before this API was introduced, to read a value from the registry, you first had to open the desired registry key containing the value calling RegOpenKeyEx. Then, you had to call the RegQueryValueEx API, dealing with many complex details. For example, if you read a string value with RegQueryValueEx, the returned string is not guaranteed to be properly NUL-terminated, which can cause a series of dangerous security bugs in your code. To prevent that from happening, you have to pay attention to check if there's a NUL terminator in the returned string; if there isn't any, you have to add it. Moreover, you have to make sure you properly close the open key, calling RegCloseKey.