Struct FunctionDesc 

#[repr(C)]
pub struct FunctionDesc {
    pub name: FfiStr,
    pub arities: *const u8,
    pub arities_len: usize,
    pub fun: Option<extern "C" fn(host: *const HostApi, args: *const GenericValue, nargs: usize) -> FfiReturn>,
}

Description of one exported plugin function.

Fields

name: FfiStr

Function name as seen from generic code.

arities: *const u8

Accepted argument counts (the host checks arity before calling).

arities_len: usize

Number of entries in arities.

fun: Option<extern "C" fn(host: *const HostApi, args: *const GenericValue, nargs: usize) -> FfiReturn>

The function implementation; a null pointer is rejected at load. The type is PluginFn spelled out inline - cbindgen only renders a nullable C function pointer for an inline Option<fn>, not through the alias.