diff --git a/.github/workflows/build-check.yaml b/.github/workflows/build-check.yaml
index 5ba583b28..68f5d0862 100644
--- a/.github/workflows/build-check.yaml
+++ b/.github/workflows/build-check.yaml
@@ -42,6 +42,18 @@ jobs:
       - name: Run clang-format dry-run
         run: find include/ src/ tests/ examples/ -iname "*.ino" -o -iname "*.h" -o -iname "*.c" | xargs clang-format -n -Werror
 
+  c99_build:
+    name: Check c99 compilation
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+  
+      - name: Build with C99
+        run: |
+          sudo apt install -y ninja-build
+          FORCE_C99=ON CMAKE_GENERATOR=Ninja make 
+
   modular_build:
     name: Modular build on ubuntu-latest
     runs-on: ubuntu-latest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c1e7bcf2c..e504c60e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -304,7 +304,7 @@ if(UNIX OR MSVC)
     target_link_libraries(z_keyexpr_canonizer ${Libname})
   endif()
 
-  if(BUILD_TESTING)
+  if(BUILD_TESTING AND CMAKE_C_STANDARD MATCHES "11")
     set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/tests")
 
     add_executable(z_data_struct_test ${PROJECT_SOURCE_DIR}/tests/z_data_struct_test.c)
diff --git a/GNUmakefile b/GNUmakefile
index e8299b14c..eac55f32a 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -37,6 +37,10 @@ BUILD_INTEGRATION?=OFF
 # Accepted values: ON, OFF
 BUILD_TOOLS?=OFF
 
+# Force the use of c99 standard.
+# Accepted values: ON, OFF
+FORCE_C99?=OFF
+
 # Debug level. This sets the ZENOH_DEBUG variable.
 # Accepted values:
 #  0: NONE
@@ -72,6 +76,10 @@ CMAKE_OPT=-DZENOH_DEBUG=$(ZENOH_DEBUG) -DBUILD_EXAMPLES=$(BUILD_EXAMPLES) -DCMAK
  -DZ_FEATURE_PUBLICATION=$(Z_FEATURE_PUBLICATION) -DZ_FEATURE_SUBSCRIPTION=$(Z_FEATURE_SUBSCRIPTION) -DZ_FEATURE_QUERY=$(Z_FEATURE_QUERY) -DZ_FEATURE_QUERYABLE=$(Z_FEATURE_QUERYABLE)\
  -DZ_FEATURE_RAWETH_TRANSPORT=$(Z_FEATURE_RAWETH_TRANSPORT) -DBUILD_INTEGRATION=$(BUILD_INTEGRATION) -DBUILD_TOOLS=$(BUILD_TOOLS) -DBUILD_SHARED_LIBS=$(BUILD_SHARED_LIBS) -H.
 
+ifeq ($(FORCE_C99), ON)
+	CMAKE_OPT += -DCMAKE_C_STANDARD=99
+endif
+
 all: make
 
 $(BUILD_DIR)/Makefile:
diff --git a/examples/unix/c99/z_get.c b/examples/unix/c99/z_get.c
index e45bfe0fe..29f844879 100644
--- a/examples/unix/c99/z_get.c
+++ b/examples/unix/c99/z_get.c
@@ -79,7 +79,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
@@ -105,7 +105,8 @@ int main(int argc, char **argv) {
     char c = '\0';
     while (1) {
         fflush(stdin);
-        scanf("%c", &c);
+        int ret = scanf("%c", &c);
+        (void)ret;  // Clear unused result warning
         if (c == 'q') {
             break;
         }
diff --git a/examples/unix/c99/z_info.c b/examples/unix/c99/z_info.c
index 901587bd8..60606c73a 100644
--- a/examples/unix/c99/z_info.c
+++ b/examples/unix/c99/z_info.c
@@ -62,7 +62,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
diff --git a/examples/unix/c99/z_pub.c b/examples/unix/c99/z_pub.c
index a03b0cc2c..f617c7741 100644
--- a/examples/unix/c99/z_pub.c
+++ b/examples/unix/c99/z_pub.c
@@ -63,7 +63,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
diff --git a/examples/unix/c99/z_pub_st.c b/examples/unix/c99/z_pub_st.c
index f62a1bd78..1bbaef106 100644
--- a/examples/unix/c99/z_pub_st.c
+++ b/examples/unix/c99/z_pub_st.c
@@ -63,7 +63,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
diff --git a/examples/unix/c99/z_pull.c b/examples/unix/c99/z_pull.c
index b809dadff..10c16d462 100644
--- a/examples/unix/c99/z_pull.c
+++ b/examples/unix/c99/z_pull.c
@@ -83,7 +83,8 @@ int main(int argc, char **argv) {
     char c = '\0';
     while (1) {
         fflush(stdin);
-        scanf("%c", &c);
+        int ret = scanf("%c", &c);
+        (void)ret;  // Clear unused result warning
         if (c == 'q') {
             break;
         }
diff --git a/examples/unix/c99/z_put.c b/examples/unix/c99/z_put.c
index 528db3785..82c259426 100644
--- a/examples/unix/c99/z_put.c
+++ b/examples/unix/c99/z_put.c
@@ -63,7 +63,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
diff --git a/examples/unix/c99/z_queryable.c b/examples/unix/c99/z_queryable.c
index d7d543789..a7c2d28af 100644
--- a/examples/unix/c99/z_queryable.c
+++ b/examples/unix/c99/z_queryable.c
@@ -74,7 +74,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
@@ -108,7 +108,8 @@ int main(int argc, char **argv) {
     char c = '\0';
     while (c != 'q') {
         fflush(stdin);
-        scanf("%c", &c);
+        int ret = scanf("%c", &c);
+        (void)ret;  // Clear unused result warning
     }
 
     z_undeclare_queryable(z_queryable_move(&qable));
diff --git a/examples/unix/c99/z_scout.c b/examples/unix/c99/z_scout.c
index 5b40a408e..e9453bf96 100644
--- a/examples/unix/c99/z_scout.c
+++ b/examples/unix/c99/z_scout.c
@@ -67,7 +67,7 @@ void callback(z_owned_hello_t *hello, void *context) {
     fprinthello(stdout, z_hello_loan(hello));
     fprintf(stdout, "\n");
     (*(int *)context)++;
-    z_drop(hello);
+    z_hello_drop(hello);
 }
 
 void drop(void *context) {
diff --git a/examples/unix/c99/z_sub.c b/examples/unix/c99/z_sub.c
index cc738e908..88c144889 100644
--- a/examples/unix/c99/z_sub.c
+++ b/examples/unix/c99/z_sub.c
@@ -67,7 +67,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");
@@ -96,7 +96,8 @@ int main(int argc, char **argv) {
     char c = '\0';
     while (c != 'q') {
         fflush(stdin);
-        scanf("%c", &c);
+        int ret = scanf("%c", &c);
+        (void)ret;  // Clear unused result warning
     }
 
     z_undeclare_subscriber(z_subscriber_move(&sub));
diff --git a/examples/unix/c99/z_sub_st.c b/examples/unix/c99/z_sub_st.c
index ceda1495f..326f5fcbc 100644
--- a/examples/unix/c99/z_sub_st.c
+++ b/examples/unix/c99/z_sub_st.c
@@ -67,7 +67,7 @@ int main(int argc, char **argv) {
         zp_config_insert(z_config_loan(&config), Z_CONFIG_CONNECT_KEY, z_string_make(clocator));
     }
     if (llocator != NULL) {
-        zp_config_insert(z_loan(config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
+        zp_config_insert(z_config_loan(&config), Z_CONFIG_LISTEN_KEY, z_string_make(llocator));
     }
 
     printf("Opening session...\n");