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POWhen is char* safe for strict pointer aliasing?
 

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    <p>I've been trying to understand the strict aliasing rules as they apply to the char pointer.</p> <p><a href="http://cellperformance.beyond3d.com/articles/2006/06/understanding-strict-aliasing.html#cast_to_char_pointer" rel="nofollow noreferrer">Here</a> this is stated:</p> <blockquote> <p>It is always presumed that a char* may refer to an alias of any object.</p> </blockquote> <p>Ok so in the context of socket code, I can do this:</p> <pre><code>struct SocketMsg { int a; int b; }; int main(int argc, char** argv) { // Some code... SocketMsg msgToSend; msgToSend.a = 0; msgToSend.b = 1; send(socket, (char*)(&amp;msgToSend), sizeof(msgToSend); }; </code></pre> <p>But then there's this statement</p> <blockquote> <p>The converse is not true. Casting a char* to a pointer of any type other than a char* and dereferencing it is usually in violation of the strict aliasing rule. </p> </blockquote> <p>Does this mean that when I recv a char array, I can't reinterpret cast to a struct when I know the structure of the message:</p> <pre><code>struct SocketMsgToRecv { int a; int b; }; int main() { SocketMsgToRecv* pointerToMsg; char msgBuff[100]; ... recv(socket, msgBuff, 100); // Ommiting make sure we have a complete message from the stream // but lets assume msgBuff[0] has a complete msg, and lets interpret the msg // SAFE!?!?!? pointerToMsg = &amp;msgBuff[0]; printf("Got Msg: a: %i, b: %i", pointerToMsg-&gt;a, pointerToMsg-&gt;b); } </code></pre> <p>Will this second example not work because the base type is a char array and I'm casting it to a struct? How do you handle this situation in a strictly aliased world?</p>
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