···

       
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    or also with <varname>crossSystem</varname>, in which case packages run on the latter, but all building happens on the former.

     

       
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    Both parameters take the same schema as the 3 (build, host, and target) platforms defined in the previous section.

     

       
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    As mentioned above, <literal>lib.systems.examples</literal> has some platforms which are used as arguments for these parameters in practice.

     

       
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    You can use them programmatically, or on the command line like <command>nix-build &lt;nixpkgs&gt; --arg crossSystem '(import &lt;nixpkgs/lib&gt;).systems.examples.fooBarBaz'</command>.

     

       
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+
       
    You can use them programmatically, or on the command line: <programlisting>

     

       
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nix-build &lt;nixpkgs&gt; --arg crossSystem '(import &lt;nixpkgs/lib&gt;).systems.examples.fooBarBaz' -A whatever</programlisting>

     

       
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  </para>

     

       
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  <para>

     

       
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    While one is free to pass both parameters in full, there's a lot of logic to fill in missing fields.