Issue #25605: Document exceptions raised by fcntl.ioctl() and fcntl.flock()
diff --git a/Doc/library/fcntl.rst b/Doc/library/fcntl.rst
index 562e78f..478c450 100644
--- a/Doc/library/fcntl.rst
+++ b/Doc/library/fcntl.rst
@@ -82,6 +82,8 @@
which is a change from versions 2.3 and 2.4. Supply the argument explicitly if
version portability is a priority.
+ If the :c:func:`ioctl` fails, an :exc:`IOError` exception is raised.
+
An example::
>>> import array, fcntl, struct, termios, os
@@ -103,6 +105,8 @@
:manpage:`flock(2)` for details. (On some systems, this function is emulated
using :c:func:`fcntl`.)
+ If the :c:func:`flock` fails, an :exc:`IOError` exception is raised.
+
.. function:: lockf(fd, operation, [length, [start, [whence]]])