Civetweb API Reference

mg_websocket_write( conn, opcode, data, data_len );


connstruct mg_connection *Connection on which the data must be written
dataconst char *Data to be written to the client
data_lensize_tLength of the data

Return Value

intNumber of bytes written or an error code


The function mg_websocket_write() sends data to a websocket client wrapped in a websocket frame. The function issues calls to mg_lock_connection() and mg_unlock_connection() 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.

The function is available only when Civetweb is compiled with the -DUSE_WEBSOCKET option.

The function returns the number of bytes written, 0 when the connection has been closed and -1 if an error occurred.

See Also