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<div class="section" id="cmp0056">
<span id="policy:CMP0056"></span><h1>CMP0056<a class="headerlink" href="#cmp0056" title="Permalink to this headline">ΒΆ</a></h1>
<p>Honor link flags in <span class="target" id="index-0-command:try_compile"></span><a class="reference internal" href="../command/try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal"><span class="pre">try_compile()</span></code></a> source-file signature.</p>
<p>The <span class="target" id="index-1-command:try_compile"></span><a class="reference internal" href="../command/try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal"><span class="pre">try_compile()</span></code></a> command source-file signature generates a
<code class="docutils literal"><span class="pre">CMakeLists.txt</span></code> file to build the source file into an executable.
In order to compile the source the same way as it might be compiled
by the calling project, the generated project sets the value of the
<span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS.html#variable:CMAKE_&lt;LANG&gt;_FLAGS" title="CMAKE_&lt;LANG&gt;_FLAGS"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS</span></code></a> variable to that in the calling project.
The value of the <span class="target" id="index-0-variable:CMAKE_EXE_LINKER_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_EXE_LINKER_FLAGS.html#variable:CMAKE_EXE_LINKER_FLAGS" title="CMAKE_EXE_LINKER_FLAGS"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_EXE_LINKER_FLAGS</span></code></a> variable may be
needed in some cases too, but CMake 3.1 and lower did not set it in
the generated project. CMake 3.2 and above prefer to set it so that
linker flags are honored as well as compiler flags. This policy
provides compatibility with the pre-3.2 behavior.</p>
<p>The OLD behavior for this policy is to not set the value of the
<span class="target" id="index-1-variable:CMAKE_EXE_LINKER_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_EXE_LINKER_FLAGS.html#variable:CMAKE_EXE_LINKER_FLAGS" title="CMAKE_EXE_LINKER_FLAGS"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_EXE_LINKER_FLAGS</span></code></a> variable in the generated test
project. The NEW behavior for this policy is to set the value of
the <span class="target" id="index-2-variable:CMAKE_EXE_LINKER_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_EXE_LINKER_FLAGS.html#variable:CMAKE_EXE_LINKER_FLAGS" title="CMAKE_EXE_LINKER_FLAGS"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_EXE_LINKER_FLAGS</span></code></a> variable in the test project
to the same as it is in the calling project.</p>
<p>If the project code does not set the policy explicitly, users may
set it on the command line by defining the
<span class="target" id="index-0-variable:CMAKE_POLICY_DEFAULT_CMP&lt;NNNN&gt;"></span><a class="reference internal" href="../variable/CMAKE_POLICY_DEFAULT_CMPNNNN.html#variable:CMAKE_POLICY_DEFAULT_CMP&lt;NNNN&gt;" title="CMAKE_POLICY_DEFAULT_CMP&lt;NNNN&gt;"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_POLICY_DEFAULT_CMP0056</span></code></a>
variable in the cache.</p>
<p>This policy was introduced in CMake version 3.2. Unlike most policies,
CMake version 3.8.2 does <em>not</em> warn by default when this policy
is not set and simply uses OLD behavior. See documentation of the
<span class="target" id="index-0-variable:CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;"></span><a class="reference internal" href="../variable/CMAKE_POLICY_WARNING_CMPNNNN.html#variable:CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;" title="CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;"><code class="xref cmake cmake-variable docutils literal"><span class="pre">CMAKE_POLICY_WARNING_CMP0056</span></code></a>
variable to control the warning.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The <code class="docutils literal"><span class="pre">OLD</span></code> behavior of a policy is
<span class="target" id="index-0-manual:cmake-policies(7)"></span><a class="reference internal" href="../manual/cmake-policies.7.html#manual:cmake-policies(7)" title="cmake-policies(7)"><code class="xref cmake cmake-manual docutils literal"><span class="pre">deprecated</span> <span class="pre">by</span> <span class="pre">definition</span></code></a>
and may be removed in a future version of CMake.</p>
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