LINUX-IPC Process Communication-pipeline

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The pipeline is one of the first UNIX IPC forms supported by Linux.

The pipe is half-duplex, the data can only flow in one direction;

A pipeline can only be responsible for data transfer in one Direction.

Two pipelines need to be established when communication between two parties is required;

Can only be used between parent-child processes or sibling processes (affinity processes);

If process a communicates with process B, you need to create two pipelines:

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A pipe can only be used for communication in one Direction, and its other direction needs to be closed.

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encapsulated pipe class, header file:

#ifndef  CPIPE_H#define CPIPE_H#include <cstddef> #define   socket int#define  INVALID_SOCKET  (SOCKET) (~0) class  tpipe{public:    tpipe (void);     ~tpipe (void)  { close ();  }    boolopen (bool  Bocanbeinherit = false)     voidclose (void)  { closereadhandle ();  Closewritehandle ();  }    intread (void * lpbuff,size_t nlength);     intwrite (const void * lpbuff,size_t nlength);     Socketgetreadhandle (void)   const { return m_nPipe[READHANDLE_INDEX]; }     socketgetwritehandle (void)   const { return m_npipe[writehandle_ Index]; }    voidclosereadhandle (void)  { closeimp (READHANDLE_INDEX);  }     voidcloSewritehandle (void)  { closeimp (writehandle_index);  }protected:    enum     {        READHANDLE_INDEX=0,         WRITEHANDLE_INDEX=1,    };     Voidcloseimp (Int nindex);    socketm_npipe[2];}; Class tpipepair{public:    tpipepair (void);     ~tpipepair (void);     boolinitex (void);     voidclose (void)     {         m_comm[0].close ();         m_comm[1].close ();     }    voidcloseina (void)      {        m_comm[0].closereadhandle ();         m_comm[1].closewritehandle ();    &nbSP;} &NBSP;&NBSP;&NBSP;&NBSP;VOIDBCLOSELNB (void)     {         m_comm[0].closewritehandle ();         m_comm[1].closereadhandle () ;     }    socketgetaproreadhandle (void)  { return m_comm [1].getreadhandle ();  }    socketgetaprowritehandle (void)  { return m_ Comm[0].getwritehandle ();  }    socketgetbproreadhandle (void)  { return  M_comm[0].getreadhandle ();  }    socketgetbprowritehandle (void)  { return  m_comm[1].getwritehandle (); }protected:    enum    {         MASTER_2_SUBMGR = 0x00,         submgr_2_master = 0x01,    };    tpipem_ COMM[2];}; #endif &nbsP;// cpipe_h 

Source file:

#include   "cpipe.h" #include  <unistd.h>tpipe::tpipe (void) {    m_npipe[0]  = invalid_socket;    m_npipe[1] = invalid_socket;} Void tpipe::closeimp (Int nindex) {    if  (m_npipe[nindex] !=  Invalid_socket)         ::close (M_npipe[nindex]);     m_npipe[nindex] = invalid_socket;} Bool tpipe::open (Bool bocanbeinherit) {    if  (pipe (m_nPipe)  == -1 )         return false;    return true;} Inttpipe::read (void * lpbuff,size_t nlength) {    if  (m_nPipe[ Readhandle_index] == invalid_socket)         return -1;     return ::read (m_npipe[readhandle_index],lpbuff,nlength);} Inttpipe::write (const Void * lpbuff,size_t nlength) {    if  (m_nPipe[WRITEHANDLE_INDEX]  == invalid_socket)         return -1;     Return ::write (m_npipe[writehandle_index],lpbuff,nlength);} Tpipepair::tpipepair (void) {}tpipepair::~tpipepair (void) {}bool tpipepair::initex (void) {     tpipepair::close ();    if  (!m_comm[submgr_2_master].open ())          return false;    else if  (!m_comm[master_2_ Submgr].open ())         return false;}

LINUX-IPC Process Communication-pipeline