Struct Desc 

#[repr(C)]
pub struct Desc {
    pub abi_version: u32,
    pub struct_size: u32,
    pub script_wire_version: u16,
    pub flags: u16,
    pub reserved: u32,
    pub name: *const c_char,
    pub version: *const c_char,
    pub init: Option<InitFn>,
    pub call: Option<HookFn>,
    pub shutdown: Option<unsafe extern "C" fn()>,
    pub free: Option<FreeFn>,
}

The descriptor a plugin’s entry function returns. Lives for the process; the host reads it after the handshake below.

abi_version and struct_size sit first and their offsets are frozen forever: the host reads them before it trusts anything else about the struct, so a future layout can still be refused with a clear error.

Fields

abi_version: u32

Must equal ABI_VERSION.

struct_size: u32

size_of::<Desc>() on the plugin side; a shorter value than the host’s own means a truncated or foreign struct.

script_wire_version: u16

lumen_script::SCRIPT_WIRE_VERSION the plugin was built against. The values, commands, and signatures it exchanges are only meaningful when it matches the host’s.

flags: u16

Bit set of FLAG_PANIC_ABORT and future flags; zero otherwise.

reserved: u32

Zero. Keeps the pointer fields below 8-aligned on every target.

name: *const c_char

NUL-terminated UTF-8, 'static. Must match the name the app declared the module under.

version: *const c_char

NUL-terminated UTF-8, 'static.

init: Option<InitFn>

Required. Runs once, before any call.

call: Option<HookFn>

Required when the manifest declares functions. input is a bincode Call, ctx is empty (the plugin already has its context from init), and out is a bincode CallOut.

shutdown: Option<unsafe extern "C" fn()>

Optional. Runs once, when the app is going down.

free: Option<FreeFn>

Required. Frees every buffer the entries above hand out.

Trait Implementations

impl Send for Desc

impl Sync for Desc