A tcp connetion question

They r two processes, for client and server, connected with TCP. Connection
is OK.
I killed the server process, while the client seems not to feel that before
it sent some data by calling send().
And it checked the errno, which indicated a segmentation fault error.

Why should it be segmentation fault rather than something indicating
disconnection?

Sorry, I realize the segmentation fault was caused by perror(). After
calling send(), the value of errno is 29, which caused perror() to crash
whole process. Confused...

However, that ain't problem. I just wanna know how to make client process
detect such situations as server killed, network
cable unplugged or anything else that can cause the disconnection?

Jimmy wrote:
> Sorry, I realize the segmentation fault was caused by perror(). After
> calling send(), the value of errno is 29, which caused perror() to crash
> whole process. Confused...
>
> However, that ain't problem. I just wanna know how to make client process
> detect such situations as server killed, network
> cable unplugged or anything else that can cause the disconnection?
>
>

Your segmentation fault indicates a bug in your program. perror()
doesn't normally crash even if the value of errno is 29 - you have tried
to write to some area that doesn't belong to you. Running the process
under gdb should tell you what caused the crash.

You detect such situations when recv() returns 0 (for an orderly
shutdown) or -1 (for an error).

Robert