第三个参数是接收的数据的实际大小。第四个参数是接收的消息的优先级。

The third argument is the actual size of the data received, and the fourth argument is the priority of the received message.

youdao

您可以将OPTCOMPIND设置为环境变量，也可以设置为配置文件中的参数，但是，将之设置为参数将优先执行。

You may either set OPTCOMPIND either as an environment variable or as a parameter in the configuration file, but setting it as a parameter will take precedence on execution.

youdao

下面按照优先级上升的顺序列出了这些参数。

The parameters are listed in ascending order of priority.

youdao