Updating trunk VERSION from 2139.0 to 2140.0

[chromium-blink-merge.git] / native_client_sdk / doc_generated / sdk / examples.html

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<section id="running-the-sdk-examples">
<span id="sdk-examples-2"></span><h1 id="running-the-sdk-examples"><span id="sdk-examples-2"></span>Running the SDK Examples</h1>
<p>Every Native Client SDK bundle comes with a folder of example applications.
Each example demonstrates one or two key Native Client programming concepts.
After you&#8217;ve <a class="reference internal" href="/native-client/sdk/download.html"><em>downloaded the SDK</em></a>, follow the instructions
on this page to build and run the examples.</p>
<p>Your version of Chrome must be equal to or greater than the version of your SDK
bundle. For example, if you&#8217;re developing with the <code>pepper_31</code> bundle, you
must use Google Chrome version 31 or greater. To find out what version of Chrome
you&#8217;re using, type <code>about:chrome</code> or <code>about:version</code> in the Chrome address
bar.</p>
<h2 id="enable-native-client">Enable Native Client</h2>
<aside class="note">
If you are using Chrome 31 or later, you can skip this section.
</aside>
<p>To run Portable Native Client applications you must specifically enable Native
Client in Chrome:</p>
<ol class="arabic">
<li><p class="first">Type <code>about:flags</code> in the Chrome address bar and scroll down to &#8220;Native
Client&#8221;.</p>
<ul class="small-gap">
<li><p class="first">If the link below &#8220;Native Client&#8221; says &#8220;Disable&#8221;, then Native Client is
already enabled and you don&#8217;t need to do anything else.</p>
</li>
</ul>
<ul class="small-gap">
<li><p class="first">If the link below &#8220;Native Client&#8221; says &#8220;Enable&#8221;, click the &#8220;Enable&#8221;
link.</p>
</li>
</ul>
</li>
<li><p class="first">Scroll down to the bottom of the page, and click &#8220;Relaunch Now&#8221;. All browser
windows will restart when you relaunch Chrome.</p>
</li>
</ol>
<h2 id="disable-the-chrome-cache">Disable the Chrome cache</h2>
<p>Chrome caches resources aggressively. When you are building a Native Client
application you should disable the cache to make sure that Chrome loads the
latest version.</p>
<ol class="arabic simple">
<li>Open Chrome&#8217;s developer tools by clicking the menu icon <img alt="menu-icon" src="/native-client/images/menu-icon.png" /> and
choosing Tools &gt; Developer tools.</li>
<li>Click the gear icon <img alt="gear-icon" src="/native-client/images/gear-icon.png" /> in the bottom right corner of the Chrome
window.</li>
<li>Under the &#8220;General&#8221; settings, check the box next to &#8220;Disable cache&#8221;.</li>
</ol>
<h2 id="build-the-sdk-examples">Build the SDK examples</h2>
<p>The Makefile scripts for the SDK examples build multiple versions of the
examples using all three SDK toolchains (newlib, glibc, and PNaCl) and in both
release and debug configurations.  (Note that some examples build only with
particular toolchains).</p>
<h3 id="build-all-examples">Build all examples</h3>
<p>To build all the examples, go to the examples directory in a specific SDK
bundle and run <code>make</code>:</p>
<pre class="prettyprint">
$ cd pepper_31/examples
$ make
make -C api  all
make[1]: Entering directory `pepper_31/examples/api'
make -C audio  all
make[2]: Entering directory `pepper_31/examples/api/audio'
  CXX  newlib/Debug/audio_x86_32.o
  LINK newlib/Debug/audio_x86_32.nexe
  CXX  newlib/Debug/audio_x86_64.o
  LINK newlib/Debug/audio_x86_64.nexe
  CXX  newlib/Debug/audio_arm.o
  LINK newlib/Debug/audio_arm.nexe
  CREATE_NMF newlib/Debug/audio.nmf
make[2]: Leaving directory `pepper_31/examples/api/audio'
make -C url_loader  all
make[2]: Entering directory `pepper_31/examples/api/url_loader'
  CXX  newlib/Debug/url_loader_x86_32.o
...
</pre>
<h3 id="build-a-single-example">Build a single example</h3>
<p>Calling <code>make</code> from inside a particular example&#8217;s directory will build only
that example:</p>
<pre class="prettyprint">
$ cd pepper_31/examples/api/core
$ make
  CXX  newlib/Debug/core_x86_32.o
  LINK newlib/Debug/core_x86_32.nexe
  CXX  newlib/Debug/core_x86_64.o
  LINK newlib/Debug/core_x86_64.nexe
  CXX  newlib/Debug/core_arm.o
  LINK newlib/Debug/core_arm.nexe
  CREATE_NMF newlib/Debug/core.nmf
</pre>
<h3 id="override-defaults">Override defaults</h3>
<p>You can call <code>make</code> with the <code>TOOLCHAIN</code> and <code>CONFIG</code> parameters to
override the defaults:</p>
<pre class="prettyprint">
$ make TOOLCHAIN=pnacl CONFIG=Release
  CXX  pnacl/Release/core_pnacl.o
  LINK pnacl/Release/core.bc
  FINALIZE pnacl/Release/core.pexe
  CREATE_NMF pnacl/Release/core.nmf
</pre>
<p>You can also set <code>TOOLCHAIN</code> to &#8220;all&#8221; to build one or more examples with
all available toolchains:</p>
<pre class="prettyprint">
$ make TOOLCHAIN=all
make TOOLCHAIN=newlib
make[1]: Entering directory `pepper_31/examples/api/core'
  CXX  newlib/Debug/core_x86_32.o
  LINK newlib/Debug/core_x86_32.nexe
  CXX  newlib/Debug/core_x86_64.o
  LINK newlib/Debug/core_x86_64.nexe
  CXX  newlib/Debug/core_arm.o
  LINK newlib/Debug/core_arm.nexe
  CREATE_NMF newlib/Debug/core.nmf
make[1]: Leaving directory `pepper_31/examples/api/core'
make TOOLCHAIN=glibc
make[1]: Entering directory `pepper_31/examples/api/core'
  CXX  glibc/Debug/core_x86_32.o
  LINK glibc/Debug/core_x86_32.nexe
  CXX  glibc/Debug/core_x86_64.o
  LINK glibc/Debug/core_x86_64.nexe
  CREATE_NMF glibc/Debug/core.nmf
make[1]: Leaving directory `pepper_31/examples/api/core'
make TOOLCHAIN=pnacl
make[1]: Entering directory `pepper_31/examples/api/core'
  CXX  pnacl/Debug/core.o
  LINK pnacl/Debug/core_unstripped.bc
  FINALIZE pnacl/Debug/core_unstripped.pexe
  CREATE_NMF pnacl/Debug/core.nmf
make[1]: Leaving directory `pepper_31/examples/api/core'
make TOOLCHAIN=linux
make[1]: Entering directory `pepper_31/examples/api/core'
  CXX  linux/Debug/core.o
  LINK linux/Debug/core.so
make[1]: Leaving directory `pepper_31/examples/api/core'
</pre>
<h2 id="build-results">Build results</h2>
<p>After running <code>make</code>, each example directory will contain one or more of
the following subdirectories:</p>
<ul class="small-gap">
<li><code>newlib</code> with subdirectories <code>Debug</code> and <code>Release</code>;</li>
<li><code>glibc</code> with subdirectories <code>Debug</code> and <code>Release</code>;</li>
<li><code>pnacl</code> with subdirectories <code>Debug</code> and <code>Release</code>;</li>
</ul>
<p>For the newlib and glibc toolchains the Debug and Release subdirectories
contain .nexe files for all target architectures. For the PNaCl toolchain
they contain a single .pexe file. PNaCl debug also produces pre-translated
.nexe files, for ease of debugging. All Debug and Release directories contain
a manifest (.nmf) file that references the associated .nexe or .pexe files.
For information about Native Client manifest files, see the <a class="reference internal" href="/native-client/overview.html"><em>Technical
Overview</em></a>.</p>
<p>For details on how to use <code>make</code>, see the <a class="reference external" href="http://www.gnu.org/software/make/manual/make.html">GNU &#8216;make&#8217; Manual</a>. For details on how to
use the SDK toolchain itself, see <a class="reference internal" href="/native-client/devguide/devcycle/building.html"><em>Building Native Client Modules</em></a>.</p>
<h2 id="run-the-sdk-examples"><span id="id1"></span>Run the SDK examples</h2>
<p>To run the SDK examples, you can use the <code>make run</code> command:</p>
<pre class="prettyprint">
$ cd pepper_31/examples/api/core
$ make run
</pre>
<p>This will launch a local HTTP server which will serve the data for the
example. It then launches Chrome with the address of this server, usually
<code>http://localhost:5103</code>. After you close Chrome, the local HTTP server is
automatically shutdown.</p>
<p>This command will try to find an executable named <code>google-chrome</code> in your
<code>PATH</code> environment variable. If it can&#8217;t, you&#8217;ll get an error message like
this:</p>
<pre class="prettyprint">
pepper_31/tools/common.mk:415: No valid Chrome found at CHROME_PATH=
pepper_31/tools/common.mk:415: *** Set CHROME_PATH via an environment variable, or command-line..  Stop.
</pre>
<p>Set the CHROME_PATH environment variable to the location of your Chrome
executable.</p>
<ul class="small-gap">
<li><p class="first">On Windows:</p>
<p>The default install location of Chrome is
<code>C:\Program Files (x86)\Google\Chrome\Application\chrome.exe</code> for Chrome
stable and
<code>C:\Users\&lt;username&gt;\AppData\Local\Google\Chrome SxS\Application\chrome.exe</code>
for Chrome Canary; try looking in those directories first:</p>
<pre class="prettyprint">
&gt; set CHROME_PATH=&lt;Path to chrome.exe&gt;
</pre>
</li>
<li><p class="first">On Linux:</p>
<pre class="prettyprint">
$ export CHROME_PATH=&lt;Path to google-chrome&gt;
</pre>
</li>
<li><p class="first">On Mac:</p>
<p>The default install location of Chrome is
<code>/Applications/Google Chrome.app/Contents/MacOS/Google Chrome</code> for
Chrome Stable and
<code>Applications/Google Chrome Canary.app/Contents/MacOS/Google Chrome Canary</code>
for Chrome Canary. Note that you have to reference the executable inside the
application bundle, not the top-level <code>.app</code> directory:</p>
<pre class="prettyprint">
$ export CHROME_PATH=&lt;Path to Google Chrome&gt;
</pre>
</li>
</ul>
<p>You can run via a different toolchain or configuration by using the
<code>TOOLCHAIN</code> and <code>CONFIG</code> parameters to make:</p>
<pre class="prettyprint">
$ make run TOOLCHAIN=pnacl CONFIG=Debug
</pre>
<h2 id="run-the-sdk-examples-as-packaged-apps"><span id="run-sdk-examples-as-packaged"></span>Run the SDK examples as packaged apps</h2>
<p>Each example can also be launched as a packaged app. For more information about
using Native Client for packaged apps, see <a class="reference internal" href="/native-client/devguide/distributing.html#distributing-packaged"><em>Packaged application</em></a>.  For general information about packaged apps, see the
<a class="reference external" href="/apps/about_apps">Chrome apps documentation</a>.</p>
<p>Some Pepper features, such as TCP/UDP socket access, are only allowed in
packaged apps. The examples that use these features must be run as packaged
apps, by using the <code>make run_package</code> command:</p>
<pre class="prettyprint">
$ make run_package
</pre>
<p>You can use <code>TOOLCHAIN</code> and <code>CONFIG</code> parameters as above to run with a
different toolchain or configuration.</p>
<h2 id="debugging-the-sdk-examples"><span id="id2"></span>Debugging the SDK examples</h2>
<p>The NaCl SDK uses <a class="reference external" href="https://www.gnu.org/software/gdb/">GDB</a> to debug Native
Client code. The SDK includes a prebuilt version of GDB that is compatible with
NaCl code. To use it, run the <code>make debug</code> command from an example directory:</p>
<pre class="prettyprint">
$ make debug
</pre>
<p>This will launch Chrome with the <code>--enable-nacl-debug</code> flag set. This flag
will cause Chrome to pause when a NaCl module is first loaded, waiting for a
connection from gdb. The <code>make debug</code> command also simultaneously launches
GDB and loads the symbols for that NEXE. To connect GDB to Chrome, in the GDB
console, type:</p>
<pre class="prettyprint">
(gdb) target remote :4014
</pre>
<p>This tells GDB to connect to a TCP port on <code>localhost:4014</code>&#8211;the port that
Chrome is listening on. GDB will respond:</p>
<pre class="prettyprint">
Remote debugging using :4014
0x000000000fa00080 in ?? ()
</pre>
<p>At this point, you can use the standard GDB commands to debug your NaCl module.
The most common commands you will use to debug are <code>continue</code>, <code>step</code>,
<code>next</code>, <code>break</code> and <code>backtrace</code>. See <a class="reference internal" href="/native-client/devguide/devcycle/debugging.html"><em>Debugging</em></a> for more information about debugging a Native Client
application.</p>
</section>

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