问题
I have a server program which should run full time a day. If I want to change some parameters of it, Is there any way rather than shut down then restart way?
回答1:
There are quite a few ways of doing this, including, but almost certainly not limited to:
You can maintain the parameters in a separate file so that the program will periodically check that file and update its internal information.
Similar to (1) but you can send some sort of signal to the application to get it to immediately re-read the file.
You can do either (1) or (2) but using shared memory rather than a configuration file.
You can have your program sit at the server end of an IPC conversation, so that a client can open up a connection to it to provide new parameters. Anything from a simple message queue to a full-blown HTTP server and associated pages.
Of course, all of these tend to need a fair amount of work in your program to get it to look for the new information.
You should take that into account when making your decision. By far the quickest solution to implement is to just (cleanly) kill off the process at something like 11:55pm then immediately restart it. It's simpler because your code probably already has the ability to load the information on startup, so this could be a simple cron one-liner.
Some people speak of laziness as a bad thing but that's not always the case :-)
回答2:
If the Server maintains many alive connections from clients, restarting the server process is the last way you should consider. Except reloading configuration files, inserting a proxy process between clients and server can be another way.
The proxy process is Responsible for 2 things.
a. Maintaining the connection from clients and forwarding packets to Server for handling.
b. Judging weather the current server process(Server A) is alive and if it not, switching to another server(Server B) automatically.
Then you can change parameters by restart server without worrying about interrupting clients since there is always two(or more) servers running.
来源：https://stackoverflow.com/questions/10101391/how-to-smooth-restart-a-c-program-without-shut-down-the-running-program