diff --git a/m-serial-json.h b/m-serial-json.h
index 188fe0f8..4578e734 100644
--- a/m-serial-json.h
+++ b/m-serial-json.h
@@ -362,7 +362,8 @@ m_serial_json_read_array_start(m_serial_local_t local, m_serial_read_t serial, s
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   int final1 = -1, final2 = -1;
-  m_core_fscanf(f, " [%n ]%n", &final1, &final2);
+  int n = m_core_fscanf(f, " [%n ]%n", &final1, &final2);
+  (void) n; // Unused. Parsing is checked through c (more robust)
   *num = 0; // don't know the size of the array.
   // Test how much the parsing succeed.
   if (final1 < 0) m_core_serial_fail();
@@ -379,7 +380,8 @@ m_serial_json_read_array_next(m_serial_local_t local, m_serial_read_t serial)
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   char c = 0;
-  m_core_fscanf(f, " %c", m_core_arg_size(&c, 1) );
+  int n = m_core_fscanf(f, " %c", m_core_arg_size(&c, 1) );
+  (void) n; // Unused. Parsing is checked through c (more robust)
   return c == ',' ? M_SERIAL_OK_CONTINUE : c == ']' ? M_SERIAL_OK_DONE : m_core_serial_fail();
 }
 
@@ -396,7 +398,8 @@ m_serial_json_read_map_start(m_serial_local_t local, m_serial_read_t serial, siz
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   int final1 = -1, final2 = -1;
-  m_core_fscanf(f, " {%n }%n", &final1, &final2);
+  int n = m_core_fscanf(f, " {%n }%n", &final1, &final2);
+  (void) n; // Unused. Parsing is checked through final (more robust)
   *num = 0; // don't know the size of the map.
   // Test how much the parsing succeed.
   if (final1 < 0) m_core_serial_fail();
@@ -412,7 +415,8 @@ m_serial_json_read_map_value(m_serial_local_t local, m_serial_read_t serial)
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   int final = -1;
-  m_core_fscanf(f, " :%n", &final);
+  int n = m_core_fscanf(f, " :%n", &final);
+  (void) n; // Unused. Parsing is checked through final (more robust)
   return final > 0 ? M_SERIAL_OK_CONTINUE : m_core_serial_fail();
 }
 
@@ -426,7 +430,8 @@ m_serial_json_read_map_next(m_serial_local_t local, m_serial_read_t serial)
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   char c = 0;
-  m_core_fscanf(f, " %c", m_core_arg_size(&c, 1) );
+  int n = m_core_fscanf(f, " %c", m_core_arg_size(&c, 1) );
+  (void) n; // Unused. Parsing is checked through c (more robust)
   return c == ',' ? M_SERIAL_OK_CONTINUE : c == '}' ? M_SERIAL_OK_DONE : m_core_serial_fail();
 }
 
@@ -439,7 +444,8 @@ m_serial_json_read_tuple_start(m_serial_local_t local, m_serial_read_t serial)
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   int final = -1;
-  m_core_fscanf(f, " {%n", &final);
+  int n = m_core_fscanf(f, " {%n", &final);
+  (void) n; // Unused. Parsing is checked through final (more robust)
   return final > 0 ? M_SERIAL_OK_CONTINUE : m_core_serial_fail();
 }
 
@@ -467,8 +473,9 @@ m_serial_json_read_tuple_id(m_serial_local_t local, m_serial_read_t serial, cons
   /* Read the field in the JSON */
   c = -1;
   char field[M_MAX_IDENTIFIER_LENGTH+1];
-  m_core_fscanf(f, " \"%" M_APPLY(M_AS_STR, M_MAX_IDENTIFIER_LENGTH) "[^ \t\n\"]\":%n",
+  int nn = m_core_fscanf(f, " \"%" M_APPLY(M_AS_STR, M_MAX_IDENTIFIER_LENGTH) "[^ \t\n\"]\":%n",
                 m_core_arg_size(field, M_MAX_IDENTIFIER_LENGTH+1), &c);
+  (void) nn ; // Unused. Check is done through 'c' (more robust).
   if (c <= 0)
     return m_core_serial_fail();
   /* Search for field in field_name */
@@ -494,15 +501,17 @@ m_serial_json_read_variant_start(m_serial_local_t local, m_serial_read_t serial,
   FILE *f = (FILE*) serial->data[0].p;
 
   int final1 = -1, final2 = -1;
-  m_core_fscanf(f, " {%n }%n", &final1, &final2);
+  int nn = m_core_fscanf(f, " {%n }%n", &final1, &final2);
+  (void) nn ; // Unused. Check is done through final (more robust).
   // Test how much the parsing succeed.
   if (final1 <= 0) return m_core_serial_fail();
   if (final2 > 0)  return M_SERIAL_OK_DONE;
 
   /* Read the field in the JSON */
   char field[M_MAX_IDENTIFIER_LENGTH+1];
-  m_core_fscanf(f, " \"%" M_APPLY(M_AS_STR, M_MAX_IDENTIFIER_LENGTH) "[^ \t\n\"]\":%n", 
+  nn = m_core_fscanf(f, " \"%" M_APPLY(M_AS_STR, M_MAX_IDENTIFIER_LENGTH) "[^ \t\n\"]\":%n", 
                 m_core_arg_size(field, M_MAX_IDENTIFIER_LENGTH+1), &final2);
+  (void) nn ; // Unused. Check is done through final (more robust).
   if (final2 <= 0) return m_core_serial_fail();
 
   /* Linear Search for field in field_name */
@@ -525,7 +534,8 @@ m_serial_json_read_variant_end(m_serial_local_t local, m_serial_read_t serial)
   (void) local; // argument not used
   FILE *f = (FILE*) serial->data[0].p;
   int final = -1;
-  m_core_fscanf(f, " }%n", &final);
+  int n = m_core_fscanf(f, " }%n", &final);
+  (void) n ; // Unused. Check is done through final (more robust).
   return final > 0 ? M_SERIAL_OK_DONE : m_core_serial_fail();
 }
 
diff --git a/tests/test-mserial-json.c b/tests/test-mserial-json.c
index 431689f1..3f3fa2ec 100644
--- a/tests/test-mserial-json.c
+++ b/tests/test-mserial-json.c
@@ -87,8 +87,8 @@ static void test_out_empty(void)
   if (!f) abort();
   static const char expected[] = "{ \"activated\":false,\"data\":{ \"vala\":0,\"valb\":0.000000,\"valc\":false,\"vald\":\"\",\"vale\":[],\"valf\":{},\"valg\":[],\"valh\":{},\"vali\":0}";
   char get[sizeof expected];
-  fgets (get, sizeof expected , f);
-  assert (strcmp(get, expected) == 0);
+  char *unused = fgets (get, sizeof expected , f);
+  assert (unused != NULL && strcmp(get, expected) == 0);
   fclose(f);
   
   f = m_core_fopen ("a-mjson.dat", "rt");
@@ -152,7 +152,8 @@ static void test_out_fill(void)
   static const char expected[] = "{ \"activated\":false,\"data\":{ \"vala\":1742,\"valb\":-2.300000,\"valc\":true,\"vald\":\"This is a test\",\"vale\":[1,2,3],\"valf\":{\"is_bool\":true},\"valg\":[1,2,3,4,5,6],\"valh\":{\"steeve\":-4,\"jane\":3},\"vali\":3}}";
   static const char expected2[] = "{ \"activated\":false,\"data\":{ \"vala\":1742,\"valb\":-2.300000,\"valc\":true,\"vald\":\"This is a test\",\"vale\":[1,2,3],\"valf\":{\"is_bool\":true},\"valg\":[1,2,3,4,5,6],\"valh\":{\"jane\":3,\"steeve\":-4},\"vali\":3}}";
   char get[sizeof expected];
-  fgets (get, sizeof expected , f);
+  char *unused2 = fgets (get, sizeof expected , f);
+  assert(unused2 != NULL);
   // Workaround  string literal of length 4350 exceeds maximum length 4095
   if (!(strcmp(get, expected) == 0 || strcmp(get, expected2) == 0))
     assert (0);