check malloc() return values

circular-buffer.c

@@ -104,6 +104,8 @@ int main(int argc, char *argv[]) {
 
   /* Add one element. */
   elem_t *one = malloc(sizeof(elem_t));
+  if (!one)
+    dienomem();
   one->foo = 23;
   cb_write(test_cb, one);
   free(one);
@@ -111,6 +113,8 @@ int main(int argc, char *argv[]) {
 
   /* Read the one element. */
   elem_t *oneback = malloc(sizeof(elem_t));
+  if (!oneback)
+    dienomem();
   cb_read(test_cb, oneback);
   assert(oneback->foo == 23);
   free(oneback);
@@ -118,6 +122,8 @@ int main(int argc, char *argv[]) {
 
   /* Fill the buffer. */
   elem_t *e = malloc(sizeof(elem_t));
+  if (!e)
+    dienomem();
   for (int i = 1; i <= CB_SIZE; i++) {
     e->foo = i;
     cb_write(test_cb, e);