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copied!<p>If you never add a constructor/destructor, assignment operators or virtual functions to your structure using malloc/free for allocation is safe.</p> <p>It's frowned upon in c++ circles, but I consider the usage of it okay if you document it in the code.</p> <p>Some comments to your code: </p> <pre><code>struct Packet { unsigned int bitlength; unsigned int data[]; }; </code></pre> <p>If I remember right declaring an array without a length is non-standard. It works on most compilers but may give you a warning. If you want to be compliant declare your array of length 1.</p> <pre><code>Packet* CreatePacket(unsigned int length) { Packet *output = (Packet*) malloc((length+1)*sizeof(unsigned int)); output->bitlength = length; return output; } </code></pre> <p>This works, but you don't take the size of the structure into account. The code will break once you add new members to your structure. Better do it this way:</p> <pre><code>Packet* CreatePacket(unsigned int length) { size_t s = sizeof (Packed) - sizeof (Packed.data); Packet *output = (Packet*) malloc(s + length * sizeof(unsigned int)); output->bitlength = length; return output; } </code></pre> <p>And write a comment into your packet structure definition that data must be the last member.</p> <p>Btw - allocating the structure and the data with a single allocation is a good thing. You halve the number of allocations that way, and you improve the locality of data as well. This can improve the performance quite a bit if you allocate lots of packages.</p> <p>Unfortunately c++ does not provide a good mechanism to do this, so you often end up with such malloc/free hacks in real world applications.</p>

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