Sockets in C

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References

Manual Pages %torch man –s 3socket … Socket, bind, listen, etc. %torch man –s 3c select

Resources section of website

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Java…

Java is a high-level language (HLL) It does a lot of work for the

programmer It hides much of the complexity of n/w

programs This can be very good, but not when

you need to understand what is happening in your programs

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… and C

C is not exactly a HLLIt has many features that are close to the operating system and processorYet if it is used carefully, with standard libraries, etc., It can be portableIt can also be an unholy mess

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Steps to Make a Server Socket

1. Make a socketLike opening a file

2. Bind a socketAttach it to a specific port

3. Tell it to accept connections(for stream sockets only)

4. Receive data into a buffer

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Socket Descriptor Sets

Sockets in C are in groups Called fd_sets (file descriptor sets) The O/S will send a signal when one

of the sockets in your fd_set has data to read

We use these in the accept loop

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The Accept Loop in C

While (1) { clear all flags set flags to say which sockets to monitor wait for accept() to return read data from socket or sockets

receive send Close

}