diff --git a/rmw_zenoh_cpp/src/detail/shm_context.cpp b/rmw_zenoh_cpp/src/detail/shm_context.cpp
index 865ff69d..51d8187a 100644
--- a/rmw_zenoh_cpp/src/detail/shm_context.cpp
+++ b/rmw_zenoh_cpp/src/detail/shm_context.cpp
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+
 #include <stdexcept>
 
 #include "shm_context.hpp"
@@ -19,13 +21,13 @@
 namespace rmw_zenoh_cpp
 {
 ///=============================================================================
-#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
 ShmContext::ShmContext(size_t alloc_size, size_t msgsize_threshold)
 :  // Create Layout for provider's memory
-   // Provider's alignment will be 1 byte as we are going to make only 1-byte aligned allocations
+   // Provider's alignment will be 1 (=2^0) bytes as we are going to make only 1-byte aligned allocations
    // TODO(yellowhatter): use zenoh_shm_message_size_threshold as base for alignment
   shm_provider(zenoh::PosixShmProvider(zenoh::MemoryLayout(alloc_size, zenoh::AllocAlignment {0}))),
   msgsize_threshold(msgsize_threshold)
 {}
-#endif
 }  // namespace rmw_zenoh_cpp
+
+#endif
diff --git a/rmw_zenoh_cpp/src/detail/shm_context.hpp b/rmw_zenoh_cpp/src/detail/shm_context.hpp
index 1c44dc58..146d9143 100644
--- a/rmw_zenoh_cpp/src/detail/shm_context.hpp
+++ b/rmw_zenoh_cpp/src/detail/shm_context.hpp
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+
 #ifndef DETAIL__SHM_CONTEXT_HPP_
 #define DETAIL__SHM_CONTEXT_HPP_
 
@@ -20,7 +22,6 @@
 namespace rmw_zenoh_cpp
 {
 ///=============================================================================
-#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
 struct ShmContext
 {
   zenoh::PosixShmProvider shm_provider;
@@ -28,7 +29,8 @@ struct ShmContext
 
   ShmContext(size_t alloc_size, size_t msgsize_threshold);
 };
-#endif
 }  // namespace rmw_zenoh_cpp
 
 #endif  // DETAIL__SHM_CONTEXT_HPP_
+
+#endif
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
index dd960529..3d4b725d 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
@@ -49,7 +49,7 @@ static const bool zenoh_shm_enabled_default = true;
 static const char * zenoh_shm_alloc_size_envar = "ZENOH_SHM_ALLOC_SIZE";
 static const size_t zenoh_shm_alloc_size_default = 1 * 1024 * 1024;
 static const char * zenoh_shm_message_size_threshold_envar = "ZENOH_SHM_MESSAGE_SIZE_THRESHOLD";
-static const size_t zenoh_shm_message_size_threshold_default = 2 * 1024;
+static const size_t zenoh_shm_message_size_threshold_default = 1; //2 * 1024;
 #endif
 
 std::optional<zenoh::Config> _get_z_config(