Type 21: Built-in Pointing Device Guide

Built-in pointing-device classification and interface information.

Result set and ownership

lazybiosGetType21 returns a lazybiosType21Array_t holding every matching structure. Iterate entries using count. A non-NULL result whose count is zero means the table contains no structure of this type; NULL means the arguments were unusable or an allocation failed. Release the set with lazybiosFreeType21, or assign it to ctx->Type21 and let lazybiosCleanup own it.

Every record carries its own SMBIOS handle and the structure length the firmware reported.

Encoded fields are decoded during parsing into decoded, which mirrors the raw member names (interface, pointing_device_type). The raw value stays alongside it, so both the encoding and its meaning are available.

Device decoding

Decode pointing_device_type with decoded.pointing_device_type and interface with decoded.interface. number_of_buttons is the reported physical button count.

Ownership

The returned structure array is allocated by the parser. Release it with lazybiosFreeType21 or assign it to lazybiosCTX::Type21 and use lazybiosCleanup.

See also

Type 21: Built-in Pointing Device