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Creation and use of cross-platform structure in C ++

I am writing a cross-platform game with network capabilities (using SFML and RakNet ), and I went to the point where I compiled the server on my Ubuntu server and got the client running on my Mac. All development is done on my Mac, so I tested the server first and it worked perfectly.

I send structover the network and then just drop them back from char *to (for example) inet::PlayerAdded. Now it works fine (for the most part), but my question is: will it always work? This seems like a very fragile approach. Will the structure always be laid out the same way, even on other platforms, such as Windows? What would you recommend?

#pragma pack(push, 1)
struct Player
{
    int dir[2];
    int left;
    float depth;
    float elevation;
    float velocity[2];
    char character[50];
    char username[50];
};

// I have been added to the game and my ID is back
struct PlayerAdded: Packet
{
    id_type id;
    Player player;
};
#pragma pack(pop)
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On the side of pure implementation: for simplicity, just assume that "unsigned int" is everywhere 32 bits aligned on a 32-bit boundary; if you can encode all your data in an array of 32-bit values, then the only externalization problem that you have to deal with is the statement.

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