diff --git a/docs/reference/testing.md b/docs/reference/testing.md
index ead66b3..81640fd 100644
--- a/docs/reference/testing.md
+++ b/docs/reference/testing.md
@@ -1317,7 +1317,9 @@
 Initializes GoogleTest. This must be called before calling
 [`RUN_ALL_TESTS()`](#RUN_ALL_TESTS). In particular, it parses the command line
 for the flags that GoogleTest recognizes. Whenever a GoogleTest flag is seen, it
-is removed from `argv`, and `*argc` is decremented.
+is removed from `argv`, and `*argc` is decremented. Keep in mind that `argv`
+must terminate with a `NULL` pointer (i.e. `argv[argc]` is `NULL`), which is
+already the case with the default `argv` passed to `main`.
 
 No value is returned. Instead, the GoogleTest flag variables are updated.