perl function pipe

The pipe function in Perl creates a pair of file handles, one for reading and the other for writing, and returns them as a list. It is commonly used to create a communication channel between two processes.

Here's an example of using pipe:

if (pipe(READER, WRITER)) {
    if (my $pid = fork()) {
        # parent process
        close(WRITER); # close the writer handle in the parent process
        while (<READER>) {
            chomp;
            print "Received message: $_\n";
        }
        close(READER); # close the reader handle in the parent process
    } else {
        # child process
        close(READER); # close the reader handle in the child process
        print WRITER "Hello, parent!\n";
        close(WRITER); # close the writer handle in the child process
        exit;
    }
} else {
    die "pipe failed: $!\n";
}

In this example, the pipe function is used to create a pair of file handles, READER and WRITER. The fork function is then called to create a child process. In the parent process, the WRITER handle is closed, and the READER handle is used to read messages sent by the child process. In the child process, the READER handle is closed, and the WRITER handle is used to send a message to the parent process. Finally, the handles are closed in each process to release the resources associated with them.