path: root/doc/user/install.in

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  <para>

  Once a program is built,
  it is often appropriate to install it in another
  directory for public use.
  You use the &Install; method 
  to arrange for a program, or any other file,
  to be copied into a destination directory:

  </para>

  <scons_example name="ex1">
     <file name="SConstruct" printme="1">
     env = Environment()
     hello = env.Program('hello.c')
     env.Install('__ROOT__/usr/bin', hello)
     </file>
     <file name="hello.c">
     int main() { printf("Hello, world!\n"); }
     </file>
  </scons_example>

  <para>

  Note, however, that installing a file is
  still considered a type of file "build."
  This is important when you remember that
  the default behavior of &SCons; is
  to build files in or below the current directory.
  If, as in the example above,
  you are installing files in a directory
  outside of the top-level &SConstruct; file's directory tree,
  you must specify that directory
  (or a higher directory, such as <literal>/</literal>)
  for it to install anything there:

  </para>

  <scons_output example="ex1">
     <scons_output_command>scons -Q</scons_output_command>
     <scons_output_command>scons -Q __ROOT__/usr/bin</scons_output_command>
  </scons_output>

  <para>

  It can, however, be cumbersome to remember
  (and type) the specific destination directory
  in which the program (or any other file)
  should be installed.
  This is an area where the &Alias;
  function comes in handy,
  allowing you, for example,
  to create a pseudo-target named <literal>install</literal>
  that can expand to the specified destination directory:

  </para>

  <scons_example name="ex2">
    <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>

  This then yields the more natural
  ability to install the program
  in its destination as follows:

  </para>

  <scons_output example="ex2">
     <scons_output_command>scons -Q</scons_output_command>
     <scons_output_command>scons -Q install</scons_output_command>
  </scons_output>

  <section>
  <title>Installing Multiple Files in a Directory</title>

    <para>

    You can install multiple files into a directory
    simply by calling the &Install; function multiple times:

    </para>

    <scons_example name="ex3">
      <file name="SConstruct" printme="1">
       env = Environment()
       hello = env.Program('hello.c')
       goodbye = env.Program('goodbye.c')
       env.Install('__ROOT__/usr/bin', hello)
       env.Install('__ROOT__/usr/bin', goodbye)
       env.Alias('install', '__ROOT__/usr/bin')
      </file>
      <file name="hello.c">
      int main() { printf("Hello, world!\n"); }
      </file>
      <file name="goodbye.c">
      int main() { printf("Goodbye, world!\n"); }
      </file>
    </scons_example>

    <para>

    Or, more succinctly, listing the multiple input
    files in a list
    (just like you can do with any other builder):

    </para>

    <sconstruct>
       env = Environment()
       hello = env.Program('hello.c')
       goodbye = env.Program('goodbye.c')
       env.Install('__ROOT__/usr/bin', [hello, goodbye])
       env.Alias('install', '__ROOT__/usr/bin')
    </sconstruct>

    <para>

    Either of these two examples yields:

    </para>

    <scons_output example="ex3">
       <scons_output_command>scons -Q install</scons_output_command>
    </scons_output>

  </section>

  <section>
  <title>Installing a File Under a Different Name</title>

    <para>

    The &Install; method preserves the name
    of the file when it is copied into the
    destination directory.
    If you need to change the name of the file
    when you copy it, use the &InstallAs; function:

    </para>

    <scons_example name="ex4">
      <file name="SConstruct" printme="1">
       env = Environment()
       hello = env.Program('hello.c')
       env.InstallAs('__ROOT__/usr/bin/hello-new', hello)
       env.Alias('install', '__ROOT__/usr/bin')
      </file>
      <file name="hello.c">
      int main() { printf("Hello, world!\n"); }
      </file>
    </scons_example>

    <para>

    This installs the <literal>hello</literal>
    program with the name <literal>hello-new</literal>
    as follows:

    </para>

    <scons_output example="ex4">
       <scons_output_command>scons -Q install</scons_output_command>
    </scons_output>

  </section>

  <section>
  <title>Installing Multiple Files Under Different Names</title>

    <para>

    Lastly, if you have multiple files that all
    need to be installed with different file names,
    you can either call the &InstallAs; function
    multiple times, or as a shorthand,
    you can supply same-length lists
    for the both the target and source arguments:

    </para>

    <scons_example name="ex5">
      <file name="SConstruct" printme="1">
       env = Environment()
       hello = env.Program('hello.c')
       goodbye = env.Program('goodbye.c')
       env.InstallAs(['__ROOT__/usr/bin/hello-new',
                      '__ROOT__/usr/bin/goodbye-new'],
                     [hello, goodbye])
       env.Alias('install', '__ROOT__/usr/bin')
      </file>
      <file name="hello.c">
      int main() { printf("Hello, world!\n"); }
      </file>
      <file name="goodbye.c">
      int main() { printf("Goodbye, world!\n"); }
      </file>
    </scons_example>

    <para>

    In this case, the &InstallAs; function
    loops through both lists simultaneously,
    and copies each source file into its corresponding
    target file name:

    </para>

    <scons_output example="ex5">
       <scons_output_command>scons -Q install</scons_output_command>
    </scons_output>

  </section>