Question

I’ve written basic server in C. The source code of the server is something like this:

int sfd;
...
read(sfd,...);
write(sfd,...);
...

and the client is:

int sfd;
...
write(sfd,...);
read(sfd,...);
...

What is the order in which those primitives are called? write(client), read(server), write(server), read(client). In this order? If not, is there a way we can ensure that?

Answer 1

write and read are blocking. It doesn’t matter which is called first. If you call read on the server before write on the client, then read will block until receives the appropriate number of bytes.