Rule (C & C++): sizeof(sizeof(...)) should not be used

<p>
A call to <code>sizeof(sizeof(...))</code> is equivalent to <code>sizeof(size_t)</code>, and therefore indicates a misuse of the <code>sizeof</code> construct.
</p>

<p>The following code:</p>

<pre>
#include &lt;string.h&gt;

int main(int argc, char* argv[])
{
  char buffer[42];
  char buffer2[sizeof(sizeof(buffer))]; /* Non-Compliant - a single sizeof() was intended */

  memcpy(buffer, "Hello, world!", strlen("Hello, world!")+1);
  memcpy(buffer2, buffer, sizeof(buffer)); /* Buffer overflow */

  return 0;
}
</pre>

<p>should be refactored into:</p>

<pre>
#include &lt;string.h&gt;

int main(int argc, char* argv[])
{
  char buffer[42];
  char buffer2[sizeof(buffer)]; /* Compliant */

  memcpy(buffer, "Hello, world!", strlen("Hello, world!")+1);
  memcpy(buffer2, buffer, sizeof(buffer));

  return 0;
}
</pre>