Function lilv_sys::lilv_world_ask

pub unsafe extern "C" fn lilv_world_ask(
    world: *mut LilvWorld, 
    subject: *const LilvNode, 
    predicate: *const LilvNode, 
    object: *const LilvNode
) -> bool

Return true iff a statement matching a certain pattern exists.

This is useful for checking if particular statement exists without having to bother with collections and memory management.

@param world The world. @param subject Subject of statement, or NULL for anything. @param predicate Predicate (key) of statement, or NULL for anything. @param object Object (value) of statement, or NULL for anything.