Your use of pointers is wrong. "pack" is already a pointer, being an array. Also, writing "PT pt" and later on "pt->id = 1" indicates you typedef'd a pointer or array type to a non-pointer type, which is bad because it makes it hard to see what is a pointer and what isn't. I strongly recommend you rewrite the code without writing any * (asterisk) in your typedef's. Then, fix the code to properly pass to memcpy and memset what they need. In any case, assuming there are no other bugs, your immediate fix is:

memcpy(pack,pt,sizeof(&pt));

But the code is not easy to follow for the reason I mentioned above, and you should rewrite it if you wish to keep your sanity.

First note, the intermediate buffer is unnecessary. You could just pass the address of the structure to enet to initialise the packet (obviously adjusting the size parameter you are passing too.

However, your structure contains a pointer. A pointer sent over the network is meaningless. One option is to change to a fixed length array, something like this:

const int MaxPacketStringLength = 100;

This has two major drawbacks, a naive client will send too much data for short strings, and it also limits the maximum size of the data.

Another way is to serialise the structure into a contiguous byte array. This is possibly what a ENetPacket is for. Enet might provide functions to help you do this. Another point is that you need to also handle endianness. Again, ENet might provide helpers, or simply expose the usual hton*() and ntoh*() functions.

Sometimes it can help if you post your current code after making changes. As I mentioned before, use [[size="3"]code] tags , or the WYSIWYG functionality in the editor to insert pretty code blocks, like this:

[[size="3"]code]

int main() {

printf("Hello, world");

}

[[size="3"]/code]

Good point, packing must be taken into consideration too. I actually meant memberwise serialisation of the structure, with "smart" handling of dynamically sized members such as strings and containers.

Is the packing of a struct standardized by C++ for POD types?

[/quote]

The OP appears to be using C, (potentially via a C++ compiler). That said, I believe neither language guarantees any sort of standard packing behaviour.

Packing and also endianess can be a problem. Explicit serialization of some kind is the most robust solution, IMO.