Not all developments systems have the same include files. The
:ref:`langext-__has_include` and :ref:`langext-__has_include_next` macros allow
you to check for the existence of an include file before doing a possibly
-failing ``#include`` directive. Include file checking macros must be used
-as expressions in #if or #elif preprocessing directives.
+failing ``#include`` directive. Include file checking macros must be used
+as expressions in ``#if`` or ``#elif`` preprocessing directives.
.. _langext-__has_include: