MPs queue, FIFO, and socketpair

Pipelines and FIFO are initially in the form of unix ipc and are rarely used. SocketPair can be used as a full-duplex MPs queue.

MPs queue

* Only used for inter-process communication with kinship
* Unidirectional, that is, half duplex (bidirectional method: 1 uses two pipelines 2 uses SocketPair)

* Pipe () => write ()/read ()

FIFO (famous Pipeline)

* It Can Be Used for unrelated inter-process communication.
* Unidirectional

* Mkfifo () => open () => write ()/read ()

SocketPair

* A socket (generally used for network communication) is used for inter-process communication between local machines.
* Bidirectional, that is, full duplex
* Socketpair () => write ()/read ()

* Example [SocketPair. cpp]:

#include 
 
  #include 
  
   #include 
   
    #include 
    
     #include 
     
      using namespace std;const int MAXSIZE = 100;int main(){    int fd[2];    int rLen;    char wBuf[MAXSIZE] = "Hello World";    char rBuf[MAXSIZE];    if (socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0)    {        cout << "SocketPair Err" << endl;        return -1;    }    pid_t pid = fork();    if (pid < 0)    {        cout << "Fork Err" << endl;        return -1;    }        if (pid == 0)    {        // Chlid        cout << "Child, Pid=" << getpid() << endl;        write(fd[0], wBuf, strlen(wBuf));        write(fd[1], wBuf, strlen(wBuf));        exit(-1);    }        // Parent    sleep(1);    cout << "Parent, Pid=" << getpid() << endl;    rLen = read(fd[1], rBuf, MAXSIZE);    rBuf[rLen] = 0;    cout << "Read Fd[1], rBuf : " << rBuf << endl;    rLen = read(fd[0], rBuf, MAXSIZE);    rBuf[rLen] = 0;    cout << "Read Fd[0], rBuf : " << rBuf << endl;    return 0;}
     
    
   
  
 

# g++ SocketPair.cpp # ./a.out Child, Pid=9569Parent, Pid=9568Read Fd[1], rBuf : Hello WorldRead Fd[0], rBuf : Hello World