core/com.nokia.carbide.cpp.compiler.doc.user/html/pragmas/p_warn_impl_s2u_conv.htm
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<h3>warn_impl_s2u_conv</h3>
<p>Controls the issuing of warnings for implicit conversions between the signed int and unsigned int data types.</p>
<h5>Syntax</h5>
<p class="code">#pragma warn_impl_s2u_conv on | off | reset
</p>
<h5>Targets</h5>
All platforms.<br />
<h5>Remarks</h5>
<p>If you enable this pragma, the compiler issues a warning for implicitly converting either from signed int to unsigned int or vice versa. Listing 10.39 provides an example.</p>
<div class="listing">
<h4>Listing 10.39 Example of Implicit Conversions Between Signed int and unsigned int</h4>
<p>#pragma warn_implicitconv on // required to enable warnings<br />
#pragma warn_impl_s2u_conv on // enable conversion warningsigned int si;<br />
unsigned int ui; </p>
<p>int main()<br />
{<br />
ui = si; // WARNING<br />
si = ui; // WARNING</p>
<p>#pragma warn_impl_s2u_conv off // disable conversion warning<br />
ui = si; // OK<br />
si = ui; // OK<br />
}</p>
</div>
<p>This pragma corresponds to the Signed / Unsigned setting . To check this setting, use <span class="code"><span class="code">__option (warn_impl_s</span>2u_conv)</span>, described in <a href="../symbols/sym_settings.htm">Checking Settings</a>. The default setting is <span class="code">off</span>.</p>
<p class="note"><strong>NOTE</strong> The setting of this pragma is ignored unless <a href="p_warn_implicitconv.htm">warn_implicitconv</a> is on.</p>
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