page.title=ndk-build
@jd:body
<div id="qv-wrapper">
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<h2>On this page</h2>
<ol>
<li><a href="#int">Internals</a></li>
<li><a href="#ifc">Invoking from the Command Line</a></li>
<li><a href="#6432">64-Bit and 32-Bit Toolchains</a></li>
<li><a href="#req">Requirements</a></li>
</ol>
</li>
</ol>
</div>
</div>
<p>The {@code ndk-build} file is a shell script introduced in Android NDK r4. Its purpose
is to invoke the right NDK build script.
<h2 id="int">Internals</h2>
<p>Running the {@code ndk-build} script is equivalent to running the following command:</p>
<pre class="no-pretty-print">
$GNUMAKE -f <ndk>/build/core/build-local.mk
<parameters>
</pre>
<p><code>$GNUMAKE</code> points to GNU Make 3.81 or later, and
<code><ndk></code> points to your NDK installation directory. You can use
this information to invoke ndk-build from other shell scripts, or even your own
make files.</p>
<h2 id="ifc">Invoking from the Command Line</h2>
<p>The {@code ndk-build} file lives in the top level the NDK installation directory. To run it
from the command line, invoke it while in or under your application project directory.
For example: </p>
<pre class="no-pretty-print">
cd <project>
$ <ndk>/ndk-build
</pre>
<p>In this example, <code><project></code> points to your
project’s root directory, and <code><ndk></code> is the directory where
you installed the NDK.</p>
<p><a class="anchor" id="options"></a> </p>
<h3>Options</h3>
<p>All parameters to ndk-build are passed directly to the underlying GNU {@code make}
command that runs the NDK build scripts. Combine <code>ndk-build</code> and
options in the form <code>ndk-build <option></code>. For example: </p>
<pre class="no-pretty-print">
$ ndk-build clean
</pre>
<p>The following options are available:</p>
<dl>
<dt>{@code clean}</dt>
<dd>Remove any previously generated binaries.</dd>
<dt>{@code V=1}</dt>
<dd>Launch build, and display build commands.<dd>
<dt>{@code -B}</dt>
<dd>Force a complete rebuild.</dd>
<dt>{@code -B V=1}</dt>
<dd>Force a complete rebuild, and display build commands.</dd>
<dt>{@code NDK_LOG=1}</dd>
<dd>Display internal NDK log messages (used for debugging the NDK itself).</dd>
<dt>{@code NDK_DEBUG=1}</dt>
<dd>Force a debuggable build (see <a href="#dvr">Table 1</a>).</dd>
<dt>{@code NDK_DEBUG=0}</dt>
<dd>Force a release build (see <a href="#dvr">Table 1</a>).</dd>
<dt>{@code NDK_HOST_32BIT=1}</dt>
<dd>Always use the toolchain in 32-bit mode (see <a href="#6432">64-bit and 32-bit
Toolchains</a>).</dd>
<dt>{@code NDK_APPLICATION_MK=<file>}</dt>
<dd>Build, using a specific <code>Application.mk</code> file pointed to by the
{@code NDK_APPLICATION_MK} variable.</dd>
<dt>{@code -C <project>}</dt>
<dd>Build the native code for the project path located at {@code <project>}. Useful if you
don't want to {@code cd} to it in your terminal.</dd>
</dl>
<p><a class="anchor" id="dvr"></a> </p>
<h3>Debuggable versus Release builds</h3>
<p>Use the <code>NDK_DEBUG</code> option and, in certain cases,
{@code AndroidManifest.xml} to specify debug or release build,
optimization-related behavior, and inclusion of symbols. Table 1 shows the
results of each possible combination of settings.</p>
<p><em>Table 1.</em> Results of <code>NDK_DEBUG</code> (command line) and
<code>android:debuggable</code> (manifest) combinations.</p>
<table>
<tr>
<th></th><th>NDK_DEBUG=0 </th><th>NDK_DEBUG=1</th><th>NDK_DEBUG not specified
</th></tr>
<tr>
<td>android:debuggble="true" </td><td>Debug; Symbols; Optimized*1
</td><td>Debug; Symbols; Not optimized*2 </td><td>(same as NDK_DEBUG=1)
</td></tr>
<tr>
<td>android:debuggable="false"</td><td>Release; Symbols; Optimized
</td><td>Release; Symbols; Not optimized</td><td>Release; No symbols;
Optimized*3 </td></tr>
</table>
*1: Useful for profiling.<br>
*2: Default for running <a href="{@docRoot}ndk/guides/ndk-gdb.html">{@code ndk-gdb}</a>.<br>
*3: Default mode.<br>
<br>
<p class="note"><strong>Note:</strong> {@code NDK_DEBUG=0} is the equivalent of
{@code APP_OPTIM=release}, and complies with the GCC {@code -O2} option. {@code NDK_DEBUG=1} is the
equivalent of {@code APP_OPTIM=debug} in {@code Application.mk}, and complies with the GCC
{@code -O0} option. For more information about {@code APP_OPTIM}, see
<a href="{@docRoot}ndk/guides/application_mk.html">Application.mk</a>.</p>
<p>The syntax on the command line is, for example: </p>
<pre class="no-pretty-print">
$ ndk-build NDK_DEBUG=1
</pre>
<p>If you are using build tools from prior to SDK r8, you must also modify your
{@code AndroidManifest.xml} file to specify debug mode. The syntax for doing so resembles the
following:</p>
<pre class="no-pretty-print"><application android:label="@string/app_name"
android:debuggable="true">
</pre>
From SDK r8 onward, you do not need to touch {@code AndroidManifest.xml}. Building a debug package
(e.g. with ant debug or the corresponding option of the ADT plugin) causes the tool automatically to
pick the native debug files generated with {@code NDK_DEBUG=1}.
<h2 id="6432">64-Bit and 32-Bit Toolchains</h2>
<p>Some toolchains come with both 64-bit and 32-bit versions. For example,
directories {@code <ndk>/toolchain/<name>/prebuilt/} and
{@code <ndk>/prebuilt/} may contain both {@code linux-x86} and
{@code linux-x86_64} folders for Linux tools in 32-bit and 64-bit modes,
respectively. The ndk-build script automatically chooses a 64-bit version of
the toolchain if the host OS supports it. You can force the use of a 32-bit
toolchain by using {@code NDK_HOST_32BIT=1} either in your environment or
on the ndk-build command line.</p>
<p>Note that 64-bit tools utilize host resources better (for instance, they are faster, and handle
larger programs), and they can still generate 32-bit binaries for Android.</p>
<h2 id="req">Requirements</h2>
<p>You need GNU Make 3.81 or later to use ndk-build or the NDK in general.
The build scripts will detect a non-compliant Make tool, and generate an error
message.</p>
<p>If you have GNU Make 3.81 installed, but the default <code>make</code>
command doesn’t launch it, define {@code GNUMAKE} in your environment to point to it
before launching ndk-build. For example: </p>
<pre class="no-pretty-print">
$ export GNUMAKE=/usr/local/bin/gmake
$ ndk-build
</pre>
<p>You can override other host prebuilt tools in {@code $NDK/prebuilt/<OS>/bin/}
with the following environment variables: </p>
<pre class="no-pretty-print">
$ export NDK_HOST_AWK=<path-to-awk>
$ export NDK_HOST_ECHO=<path-to-echo>
$ export NDK_HOST_CMP=<path-to-cmp>
</pre>