ceph/src/jaegertracing/opentelemetry-cpp/third_party/prometheus-cpp/3rdparty/civetweb/docs/api/mg_websocket_write.md

   1 # Civetweb API Reference
   2
   3 ### `mg_websocket_write( conn, opcode, data, data_len );`
   4
   5 ### Parameters
   6
   7 | Parameter | Type | Description |
   8 | :--- | :--- | :--- |
   9 |**`conn`**|`struct mg_connection *`|Connection on which the data must be written|
  10 |**`opcode`**|`int`|Opcode|
  11 |**`data`**|`const char *`|Data to be written to the client|
  12 |**`data_len`**|`size_t`|Length of the data|
  13
  14 ### Return Value
  15
  16 | Type | Description |
  17 | :--- | :--- |
  18 |`int`|Number of bytes written or an error code|
  19
  20 ### Description
  21
  22 The function `mg_websocket_write()` sends data to a websocket client wrapped in a websocket frame. The function issues calls to [`mg_lock_connection()`](mg_lock_connection.md) and [`mg_unlock_connection()`](mg_unlock_connection.md) to ensure that the transmission is not interrupted. Data corruption can otherwise happen if the application is proactively communicating and responding to a request simultaneously.
  23
  24 The function is available only when Civetweb is compiled with the `-DUSE_WEBSOCKET` option.
  25
  26 The function returns the number of bytes written, **0** when the connection has been closed and **-1** if an error occurred.
  27
  28 ### See Also
  29
  30 * [`mg_lock_connection();`](mg_lock_connection.md)
  31 * [`mg_printf();`](mg_printf.md)
  32 * [`mg_unlock_connection();`](mg_unlock_connection.md)
  33 * [`mg_websocket_client_write();`](mg_websocket_client_write.md)
  34 * [`mg_write();`](mg_write.md)