Inter process communication using named pipes(FIFO)
Earlier we saw the how to create pipes for communication between processes in linux.
One of the major disadvantage of pipes is that the they can not be accesed using their names by any other process other than child and the parent as they do not get listed in the directory tree.
The work around for this porblem is to create a named pipe which is also called as a FIFO, which stands for First in First out, meaning the data that is written into the pipe first will be read out first always.
The fifos get listed in the directory tree and any process can access it using its name by providing the approproiate path.
fifo are created using the function mkfifo() which takes as arguments
1. The name of the fifo that has to be created
2. The permissions for the file.
Once the file is created, it needs to be opened using the system call open() and the data can be read and written from the file using read() and write system calls.
One of the examples you can think of using a named pipe is communication between a server and a client. If ther are two fifos one of the server and the other of the client, then the client can send request to the server on the server fifo which the server will read and respond back with the reply on the client’s fifo.
Another advantage of a fifo over the pipes is that fifo are bidirectoinal, that is the same fifo can be read from as well and written into.
