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Diffstat (limited to 'docs/develop/cmodules.rst')
| -rw-r--r-- | docs/develop/cmodules.rst | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/docs/develop/cmodules.rst b/docs/develop/cmodules.rst index 38225e868..143057f7f 100644 --- a/docs/develop/cmodules.rst +++ b/docs/develop/cmodules.rst @@ -221,23 +221,25 @@ as described above. If a module is not enabled by default then the corresponding C preprocessor macro must be enabled. This macro name can be found by searching for the ``MP_REGISTER_MODULE`` line in the module's source code (it usually appears at the end of the main source file). -The third argument to ``MP_REGISTER_MODULE`` is the macro name, and this must be set -to 1 using ``CFLAGS_EXTRA`` to make the module available. If the third argument is just -the number 1 then the module is enabled by default. +This macro should be surrounded by a ``#if X`` / ``#endif`` pair, and the configuration +option ``X`` must be set to 1 using ``CFLAGS_EXTRA`` to make the module available. If +there is no ``#if X`` / ``#endif`` pair then the module is enabled by default. For example, the ``examples/usercmodule/cexample`` module is enabled by default so has the following line in its source code: .. code-block:: c - MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule, 1); + MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule); Alternatively, to make this module disabled by default but selectable through a preprocessor configuration option, it would be: .. code-block:: c - MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule, MODULE_CEXAMPLE_ENABLED); + #if MODULE_CEXAMPLE_ENABLED + MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule); + #endif In this case the module is enabled by adding ``CFLAGS_EXTRA=-DMODULE_CEXAMPLE_ENABLED=1`` to the ``make`` command, or editing ``mpconfigport.h`` or ``mpconfigboard.h`` to add |