GuardedFree.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
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<qhelp>

<overview>
<p>The <code>free</code> function, which deallocates heap memory, may accept a NULL pointer and take no action. Therefore, it is unnecessary to check the argument for the value of NULL before a function call to <code>free</code>. As such, these guards may hinder performance and readability.</p>
</overview>

<recommendation>
<p>A function call to <code>free</code> should not depend upon the value of its argument. Delete the condition preceding a function call to <code>free</code> when its only purpose is to check the value of the pointer to be freed.</p>
</recommendation>

<example>
<sample src = "GuardedFree.cpp" />

<p>In this example, the condition checking the value of <code>foo</code> can be deleted.</p>

</example>

<references>
<li>
    The Open Group Base Specifications Issue 7, 2018 Edition:
    <a href="https://pubs.opengroup.org/onlinepubs/9699919799/functions/free.html">free - free allocated memory</a>.
</li>
</references>

</qhelp>