ceph/src/civetweb/docs/api/mg_set_user_connection_data.md

   1 # Civetweb API Reference
   2
   3 ### `mg_set_user_connection_data( conn, data );`
   4
   5 ### Parameters
   6
   7 | Parameter | Type | Description |
   8 | :--- | :--- | :--- |
   9 |**`conn`**|`struct mg_connection *`|connection to add the user data|
  10 |**`data`**|`void *`|Pointer to the user data|
  11
  12 ### Return Value
  13
  14 *none*
  15
  16 ### Description
  17
  18 The function `mg_set_user_connection_data()` can be used to set a user defined
  19 data pointer attached to a connection.  This value can be read using
  20 `mg_get_user_connection_data()`.
  21 Any call to `mg_set_user_connection_data()` will overwrite a previously
  22 assigned user data pointer.
  23
  24 `mg_set_user_connection_data()` requires a non-const
  25 `struct mg_connection *` to set the user data pointer.  It is save to use the
  26 `const struct mg_connection *` passed to a websocket connect handler (with a
  27 const cast), since `const` just means you must not use `mg_read()` or
  28 `mg_write()` in this context.
  29
  30 Alternatively, you can use the `init_connection` callback in
  31 `struct mg_callbacks` to set the user data pointer.
  32 In this case, typically `init_connection` is used to allocate memory for
  33 a user defined `struct`, while `connection_close` is used to free this
  34 memory again.
  35
  36
  37 ### See Also
  38
  39 * [`mg_get_user_connection_data();`](mg_get_user_connection_data.md)
  40 * [`struct mg_callbacks`](mg_callbacks.md)
  41 * [`mg_set_websocket_handler();`](mg_set_websocket_handler.md)
  42 * [`mg_read();`](mg_read.md)
  43 * [`mg_write();`](mg_write.md)
  44