zephyr/samples/subsys/console/getline/README.rst
Paul Sokolovsky 542c2b93d0 subsys: console: Add pull-style console API support.
This change introduces console_getchar() and console_getline() API
calls which can be used to get pending console input (either one
char or whole line), or block waiting for one. In this regard, they
are similar to well-known ANSI C function getchar/gets/fgets, and
are intended to ease porting of existing applications to Zephyr, and
indeed, these functions (shaped as an external module) are already
used by few applications.

The implementation of the functions is structured as a new "console"
subsystem. The intention is that further generic console code may be
pulled there instead of being in drivers/console/. Besides the
functions themselves, initialization code and sample applications
are included.

At this time, there're may limitations of how these functions can
be used. For example, console_getchar() and console_getline() are
mutually exclusive, and both are incompatible with callback
(push-style) console API (and e.g. with console shell subsystem
which uses this API). Again, the intention is to make a first step
towards refactoring console subsystem to allow more flexible
real-world usage, better reusability and composability.

Change-Id: I3f4015bb5b26e0656f82f428b11ba30e980d25a0
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
2017-04-01 20:44:17 +00:00

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.. _console_getline_sample:
console_getline() Sample Application
####################################
Overview
********
This example shows how to use :cpp:func:`console_getline()` function.
Similar to the well-known ANSI C gets() and fgets() functions,
:cpp:func:`console_getline()` either returns the next available input
line or blocks waiting for one. Using this function, it should be fairly
easy to port existing ANSI C, POSIX, or Linux applications which process
console input line by line. The sample also allows to see details of how
a line is returned by the function.
If you are interested in character by character console input, see
:ref:`console_getchar_sample`.
Requirements
************
UART console is required to run this simple.
Building and Running
********************
The easiest way to run this sample is using QEMU:
.. code-block:: console
$ cd samples/console/getline
$ make BOARD=qemu_x86
$ make BOARD=qemu_x86 run
Now start pressing keys on a keyboard, followed by Enter. The input line
will be printed back, with a hex code of the last character, to show that
line does not include any special "end of line" characters (like LF, CR,
etc.)