Document Py_GETENV() (#3890)
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index 4942b1a..e654c4c 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -132,6 +132,11 @@
Argument must be a character or an integer in the range [-128, 127] or [0,
255]. This macro returns ``c`` cast to an ``unsigned char``.
+.. c:macro:: Py_GETENV(s)
+
+ Like ``getenv(s)``, but returns *NULL* if :option:`-E` was passed on the
+ command line (i.e. if ``Py_IgnoreEnvironmentFlag`` is set).
+
.. _api-objects: