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| <div class="section" id="macro"> |
| <span id="command:macro"></span><h1>macro<a class="headerlink" href="#macro" title="Permalink to this headline">¶</a></h1> |
| <p>Start recording a macro for later invocation as a command:</p> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">macro</span><span class="p">(</span><span class="o"><</span><span class="n">name</span><span class="o">></span> <span class="p">[</span><span class="n">arg1</span> <span class="p">[</span><span class="n">arg2</span> <span class="p">[</span><span class="n">arg3</span> <span class="o">...</span><span class="p">]]])</span> |
| <span class="n">COMMAND1</span><span class="p">(</span><span class="n">ARGS</span> <span class="o">...</span><span class="p">)</span> |
| <span class="n">COMMAND2</span><span class="p">(</span><span class="n">ARGS</span> <span class="o">...</span><span class="p">)</span> |
| <span class="o">...</span> |
| <span class="n">endmacro</span><span class="p">(</span><span class="o"><</span><span class="n">name</span><span class="o">></span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <p>Define a macro named <code class="docutils literal"><span class="pre"><name></span></code> that takes arguments named <code class="docutils literal"><span class="pre">arg1</span></code>, |
| <code class="docutils literal"><span class="pre">arg2</span></code>, <code class="docutils literal"><span class="pre">arg3</span></code>, (...). |
| Commands listed after macro, but before the matching |
| <span class="target" id="index-0-command:endmacro"></span><a class="reference internal" href="endmacro.html#command:endmacro" title="endmacro"><code class="xref cmake cmake-command docutils literal"><span class="pre">endmacro()</span></code></a>, are not invoked until the macro is invoked. |
| When it is invoked, the commands recorded in the macro are first |
| modified by replacing formal parameters (<code class="docutils literal"><span class="pre">${arg1}</span></code>) with the arguments |
| passed, and then invoked as normal commands. |
| In addition to referencing the formal parameters you can reference the |
| values <code class="docutils literal"><span class="pre">${ARGC}</span></code> which will be set to the number of arguments passed |
| into the function as well as <code class="docutils literal"><span class="pre">${ARGV0}</span></code>, <code class="docutils literal"><span class="pre">${ARGV1}</span></code>, <code class="docutils literal"><span class="pre">${ARGV2}</span></code>, |
| ... which will have the actual values of the arguments passed in. |
| This facilitates creating macros with optional arguments. |
| Additionally <code class="docutils literal"><span class="pre">${ARGV}</span></code> holds the list of all arguments given to the |
| macro and <code class="docutils literal"><span class="pre">${ARGN}</span></code> holds the list of arguments past the last expected |
| argument. |
| Referencing to <code class="docutils literal"><span class="pre">${ARGV#}</span></code> arguments beyond <code class="docutils literal"><span class="pre">${ARGC}</span></code> have undefined |
| behavior. Checking that <code class="docutils literal"><span class="pre">${ARGC}</span></code> is greater than <code class="docutils literal"><span class="pre">#</span></code> is the only |
| way to ensure that <code class="docutils literal"><span class="pre">${ARGV#}</span></code> was passed to the function as an extra |
| argument.</p> |
| <p>See the <span class="target" id="index-0-command:cmake_policy"></span><a class="reference internal" href="cmake_policy.html#command:cmake_policy" title="cmake_policy"><code class="xref cmake cmake-command docutils literal"><span class="pre">cmake_policy()</span></code></a> command documentation for the behavior |
| of policies inside macros.</p> |
| <div class="section" id="macro-argument-caveats"> |
| <h2>Macro Argument Caveats<a class="headerlink" href="#macro-argument-caveats" title="Permalink to this headline">¶</a></h2> |
| <p>Note that the parameters to a macro and values such as <code class="docutils literal"><span class="pre">ARGN</span></code> are |
| not variables in the usual CMake sense. They are string |
| replacements much like the C preprocessor would do with a macro. |
| Therefore you will NOT be able to use commands like:</p> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">if</span><span class="p">(</span><span class="n">ARGV1</span><span class="p">)</span> <span class="c1"># ARGV1 is not a variable</span> |
| <span class="k">if</span><span class="p">(</span><span class="n">DEFINED</span> <span class="n">ARGV2</span><span class="p">)</span> <span class="c1"># ARGV2 is not a variable</span> |
| <span class="k">if</span><span class="p">(</span><span class="n">ARGC</span> <span class="n">GREATER</span> <span class="mi">2</span><span class="p">)</span> <span class="c1"># ARGC is not a variable</span> |
| <span class="n">foreach</span><span class="p">(</span><span class="n">loop_var</span> <span class="n">IN</span> <span class="n">LISTS</span> <span class="n">ARGN</span><span class="p">)</span> <span class="c1"># ARGN is not a variable</span> |
| </pre></div> |
| </div> |
| <p>In the first case, you can use <code class="docutils literal"><span class="pre">if(${ARGV1})</span></code>. |
| In the second and third case, the proper way to check if an optional |
| variable was passed to the macro is to use <code class="docutils literal"><span class="pre">if(${ARGC}</span> <span class="pre">GREATER</span> <span class="pre">2)</span></code>. |
| In the last case, you can use <code class="docutils literal"><span class="pre">foreach(loop_var</span> <span class="pre">${ARGN})</span></code> but this |
| will skip empty arguments. |
| If you need to include them, you can use:</p> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="nb">set</span><span class="p">(</span><span class="n">list_var</span> <span class="s2">"$</span><span class="si">{ARGN}</span><span class="s2">"</span><span class="p">)</span> |
| <span class="n">foreach</span><span class="p">(</span><span class="n">loop_var</span> <span class="n">IN</span> <span class="n">LISTS</span> <span class="n">list_var</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <p>Note that if you have a variable with the same name in the scope from |
| which the macro is called, using unreferenced names will use the |
| existing variable instead of the arguments. For example:</p> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">macro</span><span class="p">(</span><span class="n">_BAR</span><span class="p">)</span> |
| <span class="n">foreach</span><span class="p">(</span><span class="n">arg</span> <span class="n">IN</span> <span class="n">LISTS</span> <span class="n">ARGN</span><span class="p">)</span> |
| <span class="p">[</span><span class="o">...</span><span class="p">]</span> |
| <span class="n">endforeach</span><span class="p">()</span> |
| <span class="n">endmacro</span><span class="p">()</span> |
| |
| <span class="n">function</span><span class="p">(</span><span class="n">_FOO</span><span class="p">)</span> |
| <span class="n">_bar</span><span class="p">(</span><span class="n">x</span> <span class="n">y</span> <span class="n">z</span><span class="p">)</span> |
| <span class="n">endfunction</span><span class="p">()</span> |
| |
| <span class="n">_foo</span><span class="p">(</span><span class="n">a</span> <span class="n">b</span> <span class="n">c</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <p>Will loop over <code class="docutils literal"><span class="pre">a;b;c</span></code> and not over <code class="docutils literal"><span class="pre">x;y;z</span></code> as one might be expecting. |
| If you want true CMake variables and/or better CMake scope control you |
| should look at the function command.</p> |
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| <ul> |
| <li><a class="reference internal" href="#">macro</a><ul> |
| <li><a class="reference internal" href="#macro-argument-caveats">Macro Argument Caveats</a></li> |
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| </li> |
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