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<?xml version='1.0'?>
<!--
SPDX-FileCopyrightText: Copyright The SCons Foundation (https://scons.org)
SPDX-License-Identifier: MIT
-->
<!DOCTYPE sconsdoc [
<!ENTITY % scons SYSTEM "../scons.mod">
%scons;
<!ENTITY % builders-mod SYSTEM "../generated/builders.mod">
%builders-mod;
<!ENTITY % functions-mod SYSTEM "../generated/functions.mod">
%functions-mod;
<!ENTITY % tools-mod SYSTEM "../generated/tools.mod">
%tools-mod;
<!ENTITY % variables-mod SYSTEM "../generated/variables.mod">
%variables-mod;
]>
<chapter id="chap-alias"
xmlns="http://www.scons.org/dbxsd/v1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.scons.org/dbxsd/v1.0 http://www.scons.org/dbxsd/v1.0/scons.xsd">
<title>Alias Targets</title>
<para>
We've already seen how you can use the &Alias;
function to create a target named <literal>install</literal>:
</para>
<scons_example name="alias_ex1">
<file name="SConstruct" printme="1">
env = Environment()
hello = env.Program('hello.c')
env.Install('__ROOT__/usr/bin', hello)
env.Alias('install', '__ROOT__/usr/bin')
</file>
<file name="hello.c">
int main() { printf("Hello, world!\n"); }
</file>
</scons_example>
<para>
You can then use this alias on the command line
to tell &SCons; more naturally that you want to install files:
</para>
<scons_output example="alias_ex1" os="posix" suffix="1">
<scons_output_command>scons -Q install</scons_output_command>
</scons_output>
<para>
Like other &Builder; methods, though,
the &Alias; method returns an object
representing the alias being built.
You can then use this object as input to anothother &Builder;.
This is especially useful if you use such an object
as input to another call to the &Alias; &Builder;,
allowing you to create a hierarchy
of nested aliases:
</para>
<scons_example name="alias_ex2">
<file name="SConstruct" printme="1">
env = Environment()
p = env.Program('foo.c')
l = env.Library('bar.c')
env.Install('__ROOT__/usr/bin', p)
env.Install('__ROOT__/usr/lib', l)
ib = env.Alias('install-bin', '__ROOT__/usr/bin')
il = env.Alias('install-lib', '__ROOT__/usr/lib')
env.Alias('install', [ib, il])
</file>
<file name="foo.c">
int main() { printf("foo.c\n"); }
</file>
<file name="bar.c">
void bar() { printf("bar.c\n"); }
</file>
</scons_example>
<para>
This example defines separate <literal>install</literal>,
<literal>install-bin</literal>,
and <literal>install-lib</literal> aliases,
allowing you finer control over what gets installed:
</para>
<scons_output example="alias_ex2" os="posix" suffix="1">
<scons_output_command>scons -Q install-bin</scons_output_command>
<scons_output_command>scons -Q install-lib</scons_output_command>
<scons_output_command>scons -Q -c __ROOT__/</scons_output_command>
<scons_output_command>scons -Q install</scons_output_command>
</scons_output>
</chapter>
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