Registration and Versioning (MATLAB COM Builder)

MATLAB COM Builder

Globally Unique Identifiers

Information is stored in the registry as keys with one or more associated named values. The keys themselves have values of primarily two types: readable strings and GUIDs. GUID is an acronym for Globally Unique Identifier, a 128-bit integer guaranteed always to be unique. The MATLAB Compiler automatically generates GUIDs for COM classes, interfaces, and type libraries that are defined within a component at build time, and codes these keys into the component's self-registration code. The interface to the system registry is directory based, and COM-related information is stored under a top-level key called HKEY_CLASSES_ROOT. Under HKEY_CLASSES_ROOT are several other keys under which the component writes its information. These keys are defined in Table C-1.

Table C-1: Keys
Key
Definition

HKEY_CLASSES_ROOT\CLSID
Information about COM classes on the system. Each component creates a new key under HKEY_CLASSES_ROOT\CLSID for each of its COM classes. The key created has a value of the GUID that has been assigned the class and contains several subkeys with information about the class.

HKEY_CLASSES_ROOT\Interface
Information about COM interfaces on the system. Each component creates a new key under HKEY_CLASSES_ROOT\Interface for each interface it defines. This key has the value of the GUID assigned to the interface and contains subkeys with information about the interface.

HKEY_CLASSES_ROOT\TypeLib
Information about type libraries on the system. Each component creates a key for its type library with the value of the GUID assigned to it. Under this key a new key is created for each version of the type library. Therefore, new versions of type libraries with the same name reuse the original GUID but create a new subkey for the new version.

HKEY_CLASSES_ROOT\<ProgID>, HKEY_CLASSES_ROOT\<VerIndProgID>
These two keys are created for the component's Program ID and Version Independent Program ID. These keys are constructed from strings of the form <component-name>.<class-name> and <component-name>.<class-name><version-number>. These keys are useful for creating a class instance from the component and class names instead of the GUIDs.

Table C-1: **Keys**
Key	Definition
`HKEY_CLASSES_ROOT\CLSID`	Information about COM classes on the system. Each component creates a new key under `HKEY_CLASSES_ROOT\CLSID` for each of its COM classes. The key created has a value of the GUID that has been assigned the class and contains several subkeys with information about the class.
`HKEY_CLASSES_ROOT\Interface`	Information about COM interfaces on the system. Each component creates a new key under `HKEY_CLASSES_ROOT\Interface` for each interface it defines. This key has the value of the GUID assigned to the interface and contains subkeys with information about the interface.
`HKEY_CLASSES_ROOT\TypeLib`	Information about type libraries on the system. Each component creates a key for its type library with the value of the GUID assigned to it. Under this key a new key is created for each version of the type library. Therefore, new versions of type libraries with the same name reuse the original GUID but create a new subkey for the new version.
`HKEY_CLASSES_ROOT\<ProgID>, HKEY_CLASSES_ROOT\<VerIndProgID>`	These two keys are created for the component's Program ID and Version Independent Program ID. These keys are constructed from strings of the form `<component-name>.<class-name>` and `<component-name>.<class-name><version-number>`. These keys are useful for creating a class instance from the component and class names instead of the GUIDs.

Self-Registering Components Versioning