CODEWITHSUNDEEP
c++linuxsockets
steveo225
steveo225

Reputation: 11882

Broken pipe when socket is closed

I have a server/client app on a Linux box. If the server is not up when the client attempts to send a request, I get a SIGPIPE and the application terminates.

How can I check if the server is available on the socket before I try to write?

Also of note, I do not want to trap the SIGPIPE because the client is really part of a shared object that is used by many applications that may or may not already define their own signal handling methods.

Thanks

Upvotes: 7

Views: 4772

Answers (2)

Zan Lynx
Zan Lynx

Reputation: 54325

This post by kroki describes what seems to be a good method.

To summarize it:

  • Check if SIGPIPE is pending. Record that in a variable. If it is pending before we even start then someone else blocked SIGPIPE. In that case skip all the signal stuff below and just do the write.
  • sigblock SIGPIPE.
  • Do the write.
  • Check if SIGPIPE is pending.
  • If it is pending then sigtimedwait for it with zero timeout.
  • Unblock SIGPIPE.

Upvotes: 0

Erik
Erik

Reputation: 91260

Pass MSG_NOSIGNAL as flags to send()

Upvotes: 7

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