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<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>

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  <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>
