Registry API

This section details the Windows Registry functions, structures, and constants used for managing the system's registry database. The registry stores configuration settings for the operating system and for applications that are designed to use the registry.

Functions

The following functions are available for interacting with the Windows Registry:

Function Name	Description
RegOpenKeyEx	Opens an existing key in the registry or creates a new key if it does not exist.
RegCreateKeyEx	Creates the specified key or opens it if it already exists.
RegCloseKey	Closes an open handle to a registry key.
RegQueryValueEx	Retrieves the data and type for a specified registry value.
RegSetValueEx	Sets the data and attributes of a specified registry value.
RegEnumKeyEx	Enumerates the subkeys of the specified open registry key.
RegDeleteKey	Deletes a subkey and its values from the registry.
RegConnectRegistry	Establishes a connection to a specified remote registry.

Structures

Key structures used with the Registry API:

Structure Name	Description
HKEY	Represents a handle to a registry key.
VALENT	Contains information about a registry value.
REG_DWORD	Data type for a 32-bit unsigned integer.
REG_SZ	Data type for a null-terminated string.

Constants

Important constants used in the Registry API:

Constant	Description
HKEY_CLASSES_ROOT	Root handle for the HKEY_CLASSES_ROOT registry key.
HKEY_CURRENT_USER	Root handle for the HKEY_CURRENT_USER registry key.
HKEY_LOCAL_MACHINE	Root handle for the HKEY_LOCAL_MACHINE registry key.
HKEY_USERS	Root handle for the HKEY_USERS registry key.
KEY_READ	Specifies read access to a registry key.
KEY_WRITE	Specifies write access to a registry key.