What methods are used for data exchange between different processes in an operating system?

Data exchange between processes (IPC, Inter-Process Communication) in operating systems can be carried out using several methods:

• Pipes — allow data to be transmitted as a stream from one process to another, typically used for parent-child communication.

• Sockets — facilitate data exchange between processes, both on the same machine and over a network.

• Shared Memory — allocates a memory region accessible by multiple processes for fast data exchange.

• Semaphores and Mutexes — used for synchronizing access to shared resources.

• Message Queues — processes exchange messages through a queue, simplifying asynchronous interaction.

• Files and Databases — processes can read and write data to shared files or databases.

Example of using a pipe in C:

int fd[2];
pipe(fd); // create a pipe
if (fork() == 0) {
  close(fd[0]); // close reading end in child
  write(fd[1], "Hello", 5);
  close(fd[1]);
} else {
  char buf[6] = {0};
  close(fd[1]); // close writing end in parent
  read(fd[0], buf, 5);
  printf("Received: %s\n", buf);
  close(fd[0]);
}

The choice of method depends on requirements for speed, data volume, and application architecture.