diff --git a/include/zenoh_commons.h b/include/zenoh_commons.h
index aecd40786..5741e3a0c 100644
--- a/include/zenoh_commons.h
+++ b/include/zenoh_commons.h
@@ -935,31 +935,6 @@ struct z_owned_publisher_t z_declare_publisher(struct z_session_t session,
  *
  *       z_subscriber_options_t opts = z_subscriber_options_default();
  *       z_owned_subscriber_t sub = z_declare_pull_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
- *
- *    Passing custom arguments to the **callback** can be done by defining a custom structure:
- *
- *    .. code-block:: C
- *
- *       typedef struct {
- *         z_keyexpr_t forward;
- *         z_session_t session;
- *       } myargs_t;
- *
- *       void callback(const z_sample_t sample, const void *arg)
- *       {
- *         myargs_t *myargs = (myargs_t *)arg;
- *         z_put(myargs->session, myargs->forward, sample->value, NULL);
- *       }
- *
- *       int main() {
- *         myargs_t cargs = {
- *           forward = z_keyexpr("forward"),
- *           session = s,
- *         };
- *         z_pull_subscriber_options_t opts = z_pull_subscriber_options_default();
- *         opts.cargs = (void *)&cargs;
- *         z_owned_pull_subscriber_t sub = z_declare_pull_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
- *       }
  */
 ZENOHC_API
 struct z_owned_pull_subscriber_t z_declare_pull_subscriber(struct z_session_t session,
@@ -1015,31 +990,6 @@ struct z_owned_queryable_t z_declare_queryable(struct z_session_t session,
  *
  *       z_subscriber_options_t opts = z_subscriber_options_default();
  *       z_owned_subscriber_t sub = z_declare_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
- *
- *    Passing custom arguments to the **callback** can be done by defining a custom structure:
- *
- *    .. code-block:: C
- *
- *       typedef struct {
- *         z_keyexpr_t forward;
- *         z_session_t session;
- *       } myargs_t;
- *
- *       void callback(const z_sample_t sample, const void *arg)
- *       {
- *         myargs_t *myargs = (myargs_t *)arg;
- *         z_put(myargs->session, myargs->forward, sample->value, NULL);
- *       }
- *
- *       int main() {
- *         myargs_t cargs = {
- *           forward = z_keyexpr("forward"),
- *           session = s,
- *         };
- *         z_subscriber_options_t opts = z_subscriber_options_default();
- *         opts.cargs = (void *)&cargs;
- *         z_owned_subscriber_t sub = z_declare_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
- *       }
  */
 ZENOHC_API
 struct z_owned_subscriber_t z_declare_subscriber(struct z_session_t session,
diff --git a/src/pull_subscriber.rs b/src/pull_subscriber.rs
index a58f911d9..931b48d84 100644
--- a/src/pull_subscriber.rs
+++ b/src/pull_subscriber.rs
@@ -24,7 +24,6 @@ use crate::LOG_INVALID_SESSION;
 use zenoh::prelude::sync::SyncResolve;
 use zenoh::prelude::SessionDeclarations;
 use zenoh::prelude::SplitBuffer;
-use zenoh::subscriber::Reliability;
 use zenoh_protocol::core::SubInfo;
 use zenoh_util::core::zresult::ErrNo;
 
@@ -148,50 +147,20 @@ pub extern "C" fn z_pull_subscriber_options_default() -> z_pull_subscriber_optio
 ///
 ///       z_subscriber_options_t opts = z_subscriber_options_default();
 ///       z_owned_subscriber_t sub = z_declare_pull_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
-///
-///    Passing custom arguments to the **callback** can be done by defining a custom structure:
-///
-///    .. code-block:: C
-///
-///       typedef struct {
-///         z_keyexpr_t forward;
-///         z_session_t session;
-///       } myargs_t;
-///   
-///       void callback(const z_sample_t sample, const void *arg)
-///       {
-///         myargs_t *myargs = (myargs_t *)arg;
-///         z_put(myargs->session, myargs->forward, sample->value, NULL);
-///       }
-///
-///       int main() {
-///         myargs_t cargs = {
-///           forward = z_keyexpr("forward"),
-///           session = s,
-///         };
-///         z_pull_subscriber_options_t opts = z_pull_subscriber_options_default();
-///         opts.cargs = (void *)&cargs;
-///         z_owned_pull_subscriber_t sub = z_declare_pull_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
-///       }
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub unsafe extern "C" fn z_declare_pull_subscriber(
+pub extern "C" fn z_declare_pull_subscriber(
     session: z_session_t,
     keyexpr: z_keyexpr_t,
     callback: &mut z_owned_closure_sample_t,
-    mut opts: *const z_pull_subscriber_options_t,
+    opts: Option<&z_pull_subscriber_options_t>,
 ) -> z_owned_pull_subscriber_t {
     let mut closure = z_owned_closure_sample_t::empty();
     std::mem::swap(callback, &mut closure);
 
     match session.upgrade() {
         Some(s) => {
-            if opts.is_null() {
-                let default = z_pull_subscriber_options_default();
-                opts = &default;
-            }
-            let reliability: Reliability = (*opts).reliability.into();
-            let res = s
+            let mut res = s
                 .declare_subscriber(keyexpr)
                 .callback(move |sample| {
                     let payload = sample.payload.contiguous();
@@ -202,10 +171,11 @@ pub unsafe extern "C" fn z_declare_pull_subscriber(
                     let sample = z_sample_t::new(&sample, &owner);
                     z_closure_sample_call(&closure, &sample)
                 })
-                .reliability(reliability)
-                .pull_mode()
-                .res();
-            match res {
+                .pull_mode();
+            if let Some(opts) = opts {
+                res = res.reliability(opts.reliability.into())
+            }
+            match res.res() {
                 Ok(sub) => z_owned_pull_subscriber_t::new(sub),
                 Err(e) => {
                     log::debug!("{}", e);
diff --git a/src/put.rs b/src/put.rs
index 3efd007b0..307c9efb4 100644
--- a/src/put.rs
+++ b/src/put.rs
@@ -117,7 +117,7 @@ pub struct z_put_options_t {
 /// Constructs the default value for :c:type:`z_put_options_t`.
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub unsafe extern "C" fn z_put_options_default() -> z_put_options_t {
+pub extern "C" fn z_put_options_default() -> z_put_options_t {
     z_put_options_t {
         encoding: z_encoding_default(),
         congestion_control: CongestionControl::default().into(),
@@ -144,22 +144,20 @@ pub unsafe extern "C" fn z_put(
     keyexpr: z_keyexpr_t,
     payload: *const u8,
     len: size_t,
-    mut opts: *const z_put_options_t,
+    opts: Option<&z_put_options_t>,
 ) -> i8 {
     match session.upgrade() {
         Some(s) => {
-            let default = z_put_options_default();
-            if opts.is_null() {
-                opts = &default;
-            }
-            match s
+            let mut res = s
                 .put(keyexpr, std::slice::from_raw_parts(payload, len))
-                .encoding((*opts).encoding)
-                .kind(SampleKind::Put)
-                .congestion_control((*opts).congestion_control.into())
-                .priority((*opts).priority.into())
-                .res_sync()
-            {
+                .kind(SampleKind::Put);
+            if let Some(opts) = opts {
+                res = res
+                    .encoding(opts.encoding)
+                    .congestion_control(opts.congestion_control.into())
+                    .priority(opts.priority.into());
+            }
+            match res.res_sync() {
                 Err(e) => {
                     log::error!("{}", e);
                     e.errno().get()
@@ -191,27 +189,23 @@ pub unsafe extern "C" fn z_put(
 ///     ``0`` in case of success, negative values in case of failure.
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub unsafe extern "C" fn zc_put_owned(
+pub extern "C" fn zc_put_owned(
     session: z_session_t,
     keyexpr: z_keyexpr_t,
     payload: Option<&mut zc_owned_payload_t>,
-    mut opts: *const z_put_options_t,
+    opts: Option<&z_put_options_t>,
 ) -> i8 {
     match session.upgrade() {
         Some(s) => {
-            let default = z_put_options_default();
-            if opts.is_null() {
-                opts = &default;
-            }
             if let Some(payload) = payload.and_then(|p| p.take()) {
-                match s
-                    .put(keyexpr, payload)
-                    .encoding((*opts).encoding)
-                    .kind(SampleKind::Put)
-                    .congestion_control((*opts).congestion_control.into())
-                    .priority((*opts).priority.into())
-                    .res_sync()
-                {
+                let mut res = s.put(keyexpr, payload).kind(SampleKind::Put);
+                if let Some(opts) = opts {
+                    res = res
+                        .encoding(opts.encoding)
+                        .congestion_control(opts.congestion_control.into())
+                        .priority(opts.priority.into());
+                }
+                match res.res_sync() {
                     Err(e) => {
                         log::error!("{}", e);
                         e.errno().get()
@@ -258,28 +252,27 @@ pub unsafe extern "C" fn z_delete_options_default() -> z_delete_options_t {
 ///     ``0`` in case of success, negative values in case of failure.
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub unsafe extern "C" fn z_delete(
+pub extern "C" fn z_delete(
     session: z_session_t,
     keyexpr: z_keyexpr_t,
-    mut opts: *const z_delete_options_t,
+    opts: Option<&z_delete_options_t>,
 ) -> i8 {
-    let default = z_delete_options_default();
-    if opts.is_null() {
-        opts = &default;
-    }
     match session.upgrade() {
-        Some(s) => match s
-            .delete(keyexpr)
-            .congestion_control((*opts).congestion_control.into())
-            .priority((*opts).priority.into())
-            .res_sync()
-        {
-            Err(e) => {
-                log::error!("{}", e);
-                e.errno().get()
+        Some(s) => {
+            let mut res = s.delete(keyexpr);
+            if let Some(opts) = opts {
+                res = res
+                    .congestion_control(opts.congestion_control.into())
+                    .priority(opts.priority.into());
             }
-            Ok(()) => 0,
-        },
+            match res.res_sync() {
+                Err(e) => {
+                    log::error!("{}", e);
+                    e.errno().get()
+                }
+                Ok(()) => 0,
+            }
+        }
         None => {
             log::debug!("{}", LOG_INVALID_SESSION);
             i8::MIN
diff --git a/src/subscriber.rs b/src/subscriber.rs
index 4d1cd4f18..910ec424b 100644
--- a/src/subscriber.rs
+++ b/src/subscriber.rs
@@ -185,63 +185,32 @@ pub extern "C" fn z_subscriber_options_default() -> z_subscriber_options_t {
 ///
 ///       z_subscriber_options_t opts = z_subscriber_options_default();
 ///       z_owned_subscriber_t sub = z_declare_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
-///
-///    Passing custom arguments to the **callback** can be done by defining a custom structure:
-///
-///    .. code-block:: C
-///
-///       typedef struct {
-///         z_keyexpr_t forward;
-///         z_session_t session;
-///       } myargs_t;
-///
-///       void callback(const z_sample_t sample, const void *arg)
-///       {
-///         myargs_t *myargs = (myargs_t *)arg;
-///         z_put(myargs->session, myargs->forward, sample->value, NULL);
-///       }
-///
-///       int main() {
-///         myargs_t cargs = {
-///           forward = z_keyexpr("forward"),
-///           session = s,
-///         };
-///         z_subscriber_options_t opts = z_subscriber_options_default();
-///         opts.cargs = (void *)&cargs;
-///         z_owned_subscriber_t sub = z_declare_subscriber(z_loan(s), z_keyexpr(expr), callback, &opts);
-///       }
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
-pub unsafe extern "C" fn z_declare_subscriber(
+pub extern "C" fn z_declare_subscriber(
     session: z_session_t,
     keyexpr: z_keyexpr_t,
     callback: &mut z_owned_closure_sample_t,
-    mut opts: *const z_subscriber_options_t,
+    opts: Option<&z_subscriber_options_t>,
 ) -> z_owned_subscriber_t {
     let mut closure = z_owned_closure_sample_t::empty();
     std::mem::swap(callback, &mut closure);
 
     match session.upgrade() {
         Some(s) => {
-            if opts.is_null() {
-                let default = z_subscriber_options_default();
-                opts = &default;
+            let mut res = s.declare_subscriber(keyexpr).callback(move |sample| {
+                let payload = sample.payload.contiguous();
+                let owner = match payload {
+                    std::borrow::Cow::Owned(v) => zenoh::buffers::ZBuf::from(v),
+                    _ => sample.payload.clone(),
+                };
+                let sample = z_sample_t::new(&sample, &owner);
+                z_closure_sample_call(&closure, &sample)
+            });
+            if let Some(opts) = opts {
+                res = res.reliability(opts.reliability.into())
             }
-            let reliability: Reliability = (*opts).reliability.into();
-            let res = s
-                .declare_subscriber(keyexpr)
-                .callback(move |sample| {
-                    let payload = sample.payload.contiguous();
-                    let owner = match payload {
-                        std::borrow::Cow::Owned(v) => zenoh::buffers::ZBuf::from(v),
-                        _ => sample.payload.clone(),
-                    };
-                    let sample = z_sample_t::new(&sample, &owner);
-                    z_closure_sample_call(&closure, &sample)
-                })
-                .reliability(reliability)
-                .res();
-            match res {
+            match res.res() {
                 Ok(sub) => z_owned_subscriber_t::new(sub),
                 Err(e) => {
                     log::debug!("{}", e);