.. _module-pw_log_basic:

------------
pw_log_basic
------------
``pw_log_basic`` is a ``pw_log backend`` that sends logs over ``pw_sys_io`` by
default. The destination of ``pw_sys_io`` depends on the ``pw_sys_io`` backend
in use. This is controlled by the ``dir_pw_sys_io_backend`` variable in a
target's ``target_config.gni``.

The log output may be changed from ``pw_sys_io`` to an arbitrary function by
calling ``pw::log_basic::SetOutput``.

.. cpp:namespace:: pw::log_basic

.. cpp:function:: void SetOutput(void (\*log_output)(std::string_view))

  Set the log output function, which defaults ``pw_sys_io::WriteLine``. This
  function is called with each formatted log message.

This module employs an internal buffer for formatting log strings, and currently
has a fixed size of 150 bytes. Any final log statements that are larger than
149 bytes (one byte used for a null terminator) will be truncated.

.. note::
  The documentation for this module is currently incomplete.