civetweb/docs/api/mg_set_user_connection_data.md

Civetweb API Reference

mg_set_user_connection_data( conn, data );

Parameters

Parameter	Type	Description
conn	struct mg_connection *	connection to add the user data
data	void *	Pointer to the user data

Return Value

none

Description

The function mg_set_user_connection_data() can be used to set a user defined data pointer attached to a connection. This value can be read using mg_get_user_connection_data(). Any call to mg_set_user_connection_data() will overwrite a previously assigned user data pointer.

mg_set_user_connection_data() requires a non-const struct mg_connection * to set the user data pointer. It is save to use the const struct mg_connection * passed to a websocket connect handler (with a const cast), since const just means you must not use mg_read() or mg_write() in this context.

Alternatively, you can use the init_connection callback in struct mg_callbacks to set the user data pointer. In this case, typically init_connection is used to allocate memory for a user defined struct, while connection_close is used to free this memory again.

See Also

• mg_get_user_connection_data();
• struct mg_callbacks
• mg_set_websocket_handler();
• mg_read();
• mg_write();