[ENet-discuss] sending and receiving structs from eNet

[Nathan Pritchard]

Quite a few things you need to consider, I'll cover (what I think are) 
the main two:

1) You're not sending the strings for 'username' or 'password', etc. 
You're sending pointers. Think about that, you're sending a (in the case 
of your 32-bit machine) 4-byte memory address to another client.

2) You need to read up Endianness and understand host and network byte 
ordering. Bytes ordering for numbers (ints, float, etc) are interpreted 
differently by different OSs.

Consider writing a serialization/deserialization routine for handling 
these structs. If you want to be sending dynamically sized structures 
with data that needs to be interpreted, you can't just memcpy unfortunately.


On 29/04/2016 17:52, Amir Ramezani wrote:
> hello all,
> i want to send struct using eNet, the structure definition is like this:
> //the structure that represents the game data to be sent
> typedef struct gamedata
> {
> const char *username;
> const char *password;
> int rank;
> bool userpass_incorrect;
> bool account_not_exist;
> const char *mac_address;
> const char *hdd_serial;
> const char *ip_address;
> int x;
> int y;
> int z;
> int health;
> bool is_banned;
> bool notify;
> const char *pm_user;
> const char *chat_user;
> const char *message;
> const char *server_message;
> const char *motd;
> bool came_online;
> bool went_offline;
> }gamedata;
>
> now, when my server receive's this struct from client, it crashe's
> size is the size of packet that had been received, and data is the
> packet content variable
> and gd is the structure that i want to process
> i use memcpy to copy from data to struct:
> memcpy(gd, data+size, sizeof(*data) +size);
> but when i receive it, and want to process it, (dirring the
> debugging), i just get a memory access problem
> what am i doing wrong?
> compiler: gcc 5.3.0
> using gnu++14,
> ide:code::blocks
> debugger: gdb
> operating system: windows7 ultimate 32 bit
> thanks
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