Function blpapi_ProviderSession_registerServiceAsync 

pub unsafe extern "C" fn blpapi_ProviderSession_registerServiceAsync(
    session: *mut blpapi_ProviderSession_t,
    serviceName: *const c_char,
    identity: *const blpapi_Identity_t,
    correlationId: *mut blpapi_CorrelationId_t,
    registrationOptions: *mut blpapi_ServiceRegistrationOptions_t,
) -> c_int