How to make my program aware of environ HTTP_PROXY, SOCKS_PROXY?

Shou开发者_如何学JAVAld I have to read these vars and make my own abstract connection layer? Is there any high level network access library can do it for me?

I'd like to know those libraries take care of HTTP_PROXY, SOCKS_PROXY vars, for Java, C and all.

You can use the HTTP Proxy Client Library. It will replace the connect function. By this you do not need to change your program. The library will transparently connect to a proxy specified in the environment.