Application Folder
==================
Contents
--------
General
Directory Location
Named Applications
Named Startup main() function
NuttShell (NSH) Built-In Commands
Application Configuration File
Example Named Application
General
-------
This folder provides various applications found in sub-directories. These
applications are not inherently a part of NuttX but are provided you help
you develop your own applications. The apps/ directory is a "break away"
part of the configuration that you may chose to use or not.
Directory Location
------------------
The default application directory used by the NuttX build should be named
apps/ (or apps-x.y/ where x.y is the NuttX version number). This apps/
directoy should appear in the directory tree at the same level as the
NuttX directory. Like:
.
|- nuttx
|
`- apps
If all of the above conditions are TRUE, then NuttX will be able to
find the application directory. If your application directory has a
different name or is location at a different position, then you will
have to inform the NuttX build system of that location. There are several
ways to do that:
1) You can define CONFIG_APPS_DIR to be the full path to your application
directory in the NuttX configuration file.
2) You can provide the path to the application directory on the command line
like: make APPDIR=<path> or make CONFIG_APPS_DIR=<path>
3) When you configure NuttX using tools/configure.sh, you can provide that
path to the application directory on the configuration command line
like: ./configure.sh -a <app-dir> <board-name>/<config-name>
Named Applications
------------------
NuttX also supports applications that can be started using a name string.
In this case, zpplication entry points with their requirements are gathered
together in two files:
- namedapp/namedapp_proto.h Entry points, prototype function
- namedapp/namedapp_list.h Application specific information and requirements
The build occurs in several phases as different build targets are executed:
(1) context, (2) depend, and (3) default (all). Application information is
collected during the make context build phase.
To execute an application function:
exec_namedapp() is defined in the nuttx/include/apps/apps.h
NuttShell (NSH) Built-In Commands
---------------------------------
One use of named applications is to provide a way of invoking your custom
application through the NuttShell (NSH) command line. NSH will support
a seamless method invoking the applications, when the following option is
enabled in the NuttX configuration file:
CONFIG_NSH_BUILTIN_APPS=y
Application Configuration File
------------------------------
A special configuration file is used to configure which applications
are to be included in the build. The source for this file is
configs/<board>/<configuration>/appconfig. The existence of the appconfig
file in the board configuration directory is sufficient to enable building
of applications.
The appconfig file is copied into the apps/ directory as .config when
NuttX is configured. .config is included in the toplevel apps/Makefile.
As a minimum, this configuration file must define files to add to the
CONFIGURED_APPS list like:
CONFIGURED_APPS += vsn/hello vsn/poweroff vsn/jvm
Named Start-Up main() function
------------------------------
A named application can even be used as the main, start-up entry point
into your embedded software. When the user defines this option in
the NuttX configuration file:
CONFIG_BUILTIN_APP_START=<application name>
that application shall be invoked immediately after system starts
*instead* of the normal, default "user_start" entry point.
Note that <application name> must be provided as: "hello",
will call:
int hello_main(int argc, char *argv[])
Example Named Application
-------------------------
An example application skeleton can be found under the vsn/hello
sub-directory. This example shows how a named application can be added
to the project. One must define:
1. create sub-directory as: appname
2. provide entry point: appname_main()
3. set the requirements in the file: Makefile, specially the lines:
APPNAME = appname
PRIORITY = SCHED_PRIORITY_DEFAULT
STACKSIZE = 768
ASRCS = asm source file list as a.asm b.asm ...
CSRCS = C source file list as foo1.c foo2.c ..
4. add application in the apps/.config
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