The RegQueryInfoKey function retrieves information about a specified registry key.
LONG RegQueryInfoKey(
HKEY hKey, // handle to key to query
LPTSTR lpClass, // address of buffer for class string
LPDWORD lpcbClass, // address of size of class string buffer
LPDWORD lpReserved, // reserved
LPDWORD lpcSubKeys, // address of buffer for number of
// subkeys
LPDWORD lpcbMaxSubKeyLen, // address of buffer for longest subkey
// name length
LPDWORD lpcbMaxClassLen, // address of buffer for longest class
// string length
LPDWORD lpcValues, // address of buffer for number of value
// entries
LPDWORD lpcbMaxValueNameLen, // address of buffer for longest
// value name length
LPDWORD lpcbMaxValueLen, // address of buffer for longest value
// data length
LPDWORD lpcbSecurityDescriptor,
// address of buffer for security
// descriptor length
PFILETIME lpftLastWriteTime // address of buffer for last write
// time
);
HKEY_CLASSES_ROOT
HKEY_CURRENT_CONFIG
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
Windows NT: HKEY_PERFORMANCE_DATA
Windows 95 and Windows 98: HKEY_DYN_DATA
If lpClass is NULL, lpcbClass can be NULL.
Windows NT: If the lpClass parameter is a valid address, but the lpcbClass parameter is not (for example, it is NULL), the function returns ERROR_INVALID_PARAMETER.
Windows 95: If the lpClass parameter is a valid address, but the lpcbClass parameter is not (for example, it is NULL), the function returns ERROR_SUCCESS instead of ERROR_INVALID_PARAMETER. To ensure compatibility with other platforms, verify that lpcbClass is valid before calling the function.
Windows NT: The function sets the members of the FILETIME structure to indicate the last time that the key or any of its value entries was modified.
Windows 95: The function sets the members of the FILETIME structure to zero. This is because the system does not keep track of registry key last write time information.
If the function succeeds, the return value is ERROR_SUCCESS.
If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.
The key identified by the hKey parameter must have been opened with KEY_QUERY_VALUE access (KEY_READ access includes KEY_QUERY_VALUE access).
Windows CE: The lpcbMaxValueData and lpcbSecurityDescriptor parameters are not used and must be set to NULL.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winreg.h.
Import Library: Use advapi32.lib.
Unicode: Implemented as Unicode and ANSI versions on Windows NT.
Registry Overview, Registry Functions, FILETIME, RegDeleteKey, RegEnumKey, RegEnumKeyEx, RegEnumValue, RegQueryValue, RegQueryValueEx