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| <div class="section" id="function"> |
| <span id="command:function"></span><h1>function<a class="headerlink" href="#function" title="Permalink to this headline">¶</a></h1> |
| <p>Start recording a function for later invocation as a command.</p> |
| <div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">function(</span><span class="nv"><name></span><span class="w"> </span><span class="p">[</span><span class="nv"><arg1></span><span class="w"> </span><span class="p">...]</span><span class="nf">)</span><span class="w"></span> |
| <span class="w"> </span><span class="nv"><commands></span><span class="w"></span> |
| <span class="nf">endfunction()</span><span class="w"></span> |
| </pre></div> |
| </div> |
| <p>Defines a function named <code class="docutils literal notranslate"><span class="pre"><name></span></code> that takes arguments named |
| <code class="docutils literal notranslate"><span class="pre"><arg1></span></code>, ... The <code class="docutils literal notranslate"><span class="pre"><commands></span></code> in the function definition |
| are recorded; they are not executed until the function is invoked.</p> |
| <p>Per legacy, the <span class="target" id="index-0-command:endfunction"></span><a class="reference internal" href="endfunction.html#command:endfunction" title="endfunction"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">endfunction()</span></code></a> command admits an optional |
| <code class="docutils literal notranslate"><span class="pre"><name></span></code> argument. If used, it must be a verbatim repeat of the |
| argument of the opening <code class="docutils literal notranslate"><span class="pre">function</span></code> command.</p> |
| <p>A function opens a new scope: see <span class="target" id="index-0-command:set"></span><a class="reference internal" href="set.html#command:set" title="set"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">set(var</span> <span class="pre">PARENT_SCOPE)</span></code></a> for |
| details.</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 notranslate"><span class="pre">cmake_policy()</span></code></a> command documentation for the behavior |
| of policies inside functions.</p> |
| <p>See the <span class="target" id="index-0-command:macro"></span><a class="reference internal" href="macro.html#command:macro" title="macro"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">macro()</span></code></a> command documentation for differences |
| between CMake functions and macros.</p> |
| <div class="section" id="invocation"> |
| <h2>Invocation<a class="headerlink" href="#invocation" title="Permalink to this headline">¶</a></h2> |
| <p>The function invocation is case-insensitive. A function defined as</p> |
| <div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">function(</span><span class="nb">foo</span><span class="nf">)</span><span class="w"></span> |
| <span class="w"> </span><span class="nv"><commands></span><span class="w"></span> |
| <span class="nf">endfunction()</span><span class="w"></span> |
| </pre></div> |
| </div> |
| <p>can be invoked through any of</p> |
| <div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">foo()</span><span class="w"></span> |
| <span class="nf">Foo()</span><span class="w"></span> |
| <span class="nf">FOO()</span><span class="w"></span> |
| <span class="nf">cmake_language(</span><span class="no">CALL</span><span class="w"> </span><span class="nb">foo</span><span class="nf">)</span><span class="w"></span> |
| </pre></div> |
| </div> |
| <p>and so on. However, it is strongly recommended to stay with the |
| case chosen in the function definition. Typically functions use |
| all-lowercase names.</p> |
| <div class="versionadded"> |
| <p><span class="versionmodified added">New in version 3.18: </span>The <span class="target" id="index-0-command:cmake_language"></span><a class="reference internal" href="cmake_language.html#command:cmake_language" title="cmake_language"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">cmake_language(CALL</span> <span class="pre">...)</span></code></a> command can also be used to |
| invoke the function.</p> |
| </div> |
| </div> |
| <div class="section" id="arguments"> |
| <h2>Arguments<a class="headerlink" href="#arguments" title="Permalink to this headline">¶</a></h2> |
| <p>When the function is invoked, the recorded <code class="docutils literal notranslate"><span class="pre"><commands></span></code> are first |
| modified by replacing formal parameters (<code class="docutils literal notranslate"><span class="pre">${arg1}</span></code>, ...) with the |
| arguments passed, and then invoked as normal commands.</p> |
| <p>In addition to referencing the formal parameters you can reference the |
| <code class="docutils literal notranslate"><span class="pre">ARGC</span></code> variable which will be set to the number of arguments passed |
| into the function as well as <code class="docutils literal notranslate"><span class="pre">ARGV0</span></code>, <code class="docutils literal notranslate"><span class="pre">ARGV1</span></code>, <code class="docutils literal notranslate"><span class="pre">ARGV2</span></code>, ... which |
| will have the actual values of the arguments passed in. This facilitates |
| creating functions with optional arguments.</p> |
| <p>Furthermore, <code class="docutils literal notranslate"><span class="pre">ARGV</span></code> holds the list of all arguments given to the |
| function and <code class="docutils literal notranslate"><span class="pre">ARGN</span></code> holds the list of arguments past the last expected |
| argument. Referencing to <code class="docutils literal notranslate"><span class="pre">ARGV#</span></code> arguments beyond <code class="docutils literal notranslate"><span class="pre">ARGC</span></code> have |
| undefined behavior. Checking that <code class="docutils literal notranslate"><span class="pre">ARGC</span></code> is greater than <code class="docutils literal notranslate"><span class="pre">#</span></code> is |
| the only way to ensure that <code class="docutils literal notranslate"><span class="pre">ARGV#</span></code> was passed to the function as an |
| extra argument.</p> |
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| <h3><a href="../index.html">Table of Contents</a></h3> |
| <ul> |
| <li><a class="reference internal" href="#">function</a><ul> |
| <li><a class="reference internal" href="#invocation">Invocation</a></li> |
| <li><a class="reference internal" href="#arguments">Arguments</a></li> |
| </ul> |
| </li> |
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