comand read, write. use in socket

Hello everyone :),
i'm making a client-server system with comunication through socket.
More clients write on the same socket and, for the specifications, i have to use the command write and read.

When the server run the read on the socket, this take all messages present.
But i want take only one message, the first.
I don't know the size of message and so i read max 1024 characters. For this reason i read on the socket all messages contained in 1024 characters.
These message are separated by "\n".


Please help me with a example that resolve my problem or with good explanation

So read the first message, and store everything that isn't part of the first message as the next pending message. Otherwise, you are going to have to make single byte read calls until you happen to run into a \n, at which point you stop reading for messages. Pick one. (This concept is suspiciously similar to checking for a single word or sentence in a file!)


Quzah.

Hmm....where have I seen this before? Oh yeah, I remember:

How do I read/write from a socket - Cboard-FAQ

:rolleyes::tongue:

Ok perfect, in my specifications it's solution is recommended.

Quote:

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Solution 2 - Use a data length indicator
Every message that is sent can be prefixed with a value that represents the data's length. The receiver starts by recv()ing a fixed number of bytes to get this length indicator and, once it has it, it recv()s that specific number of bytes. If all goes well, two recv()s are all that are needed to read one message. Of course, the data may be split, meaning that you need two or more calls to get it... and don't forget this includes the getting of the length indicator in the first place!

---

But i don't understand how implement this.
I read, for example, "0017This is a message0010So is this".
So i have to elaborate the first message and save the second in a list of pending message?
Not exists a method for change the pointer to file socket to next string.
That is, I read "0017This is a message0010So is this" then i get "0017This is a message" and change the pointer of socket to position 21 -> so next time i read "0010So is this".

I hope that I explained well.
Thanks

Read an int. See what it is. Read that many bytes. Read another int. Repeat until bored.


Quzah.

Well think about the message for a little bit.

"0017This is a message
0010So is this"

There are two very obvious parts of this. The length sent over is how many bytes you should read next, so you do that. And then you keep listening to get the next number, then read N bytes again.

Rinse. Repeat.

Edit - foiled again!