diff --git a/lib/nss.c b/lib/nss.c
index 9174e97b..0f414e18 100644
--- a/lib/nss.c
+++ b/lib/nss.c
@@ -131,9 +131,9 @@ void nss_init(const char *nsswitch_path) {
 		fprintf(shadow_logfd, "%s did not provide @find_subid_owners@\n", libname);
 		goto close_lib;
 	}
-	subid_nss->free= dlsym(h, "shadow_subid_free");
+	subid_nss->free = dlsym(h, "shadow_subid_free");
 	if (!subid_nss->free) {
-		// Fallback to default `free()` for backward compatibility.
+		// Fallback to free(3) for backward compatibility.
 		subid_nss->free = free;
 	}
 	subid_nss->handle = h;
diff --git a/lib/prototypes.h b/lib/prototypes.h
index 7e2f5d22..1307c132 100644
--- a/lib/prototypes.h
+++ b/lib/prototypes.h
@@ -292,7 +292,7 @@ struct subid_nss_ops {
 	 * Some routines of subid_nss_ops allocate memory which should be freed by
 	 * caller after use. In order to deallocate that memory block, one should
 	 * use this routine to release that memory. By default, this function
-	 * pointer is set to free() for backward compatibility. However, it is
+	 * pointer is set to free(3) for backward compatibility. However, it is
 	 * strongly recommended to define this routine explicitly.
 	 */
 	void (*free)(void *ptr);