Doc: change 'Posix' for 'POSIX' (GH-20001)
diff --git a/Doc/howto/sockets.rst b/Doc/howto/sockets.rst
index 4655f28..d6ed128 100644
--- a/Doc/howto/sockets.rst
+++ b/Doc/howto/sockets.rst
@@ -319,7 +319,7 @@
In Python, you use ``socket.setblocking(False)`` to make it non-blocking. In C, it's
more complex, (for one thing, you'll need to choose between the BSD flavor
-``O_NONBLOCK`` and the almost indistinguishable Posix flavor ``O_NDELAY``, which
+``O_NONBLOCK`` and the almost indistinguishable POSIX flavor ``O_NDELAY``, which
is completely different from ``TCP_NODELAY``), but it's the exact same idea. You
do this after creating the socket, but before using it. (Actually, if you're
nuts, you can switch back and forth.)