Code--QQ Chat implementation (based on the Linux pipeline Signal sharing memory)

One: Description of tasks

             a b Two processes communicate through pipelines, like they used to chat with each other, and then a process receives data each time through a1 process display (a new process for displaying a The information received), a a1 The data transfer between the use of shared memory, corresponding to a b1 process. Used to display the information received by the b process.

For A,B process, exit with CTRL + C exit, when the corresponding signal is received. The process can be cleaned by the signal processing function, and exit exits the process after cleanup . (A1,B1, manual shutdown is possible). interface diagrams such as the following.

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two : Code show

A process

#include <stdlib.h> #include <stdio.h> #include <string.h> #include <sys/shm.h> #include < sys/sem.h> #include <unistd.h> #include <sys/ipc.h> #include <sys/time.h> #include <fcntl.h > #include <sys/types.h> #include <sys/stat.h> #include <signal.h>int shm_id;struct t{Char buf[1 28];};        struct T *p;void hanle (int sig) {SHMDT (P);        Shmctl (shm_id,ipc_rmid,null);//delete shared memory printf ("delete ok........\n"); Exit (0);} int main () {//a process signal (SIGINT,HANLE);//capture CTRL + C signal Shm_id=shmget ((key_t) 1234,4096,0600|        Ipc_creat);//Create a shared memory//struct T *p;        p= (struct t*) Shmat (shm_id,null,0);//Get the memory pointer structure int F1;        F1=open ("1.fifo", o_wronly);//Open write-end int F2 to 1;        F2=open ("2.fifo", o_rdonly);//to 2 open read-end fd_set Readset;        Defines the readable set int maxfd; Maxfd=stdin_fileno > F2?
stdin_fileno+1:f2+1;        struct Timeval check;        check.tv_sec=1;//set viewing time is one second char buf[128]; while (1) {Fd_zero (&readset);//Initialize Fd_set (stdin_fileno,&readset);//Join the Monitoring object Fd_set (F2         , &readset); Select (Maxfd,&readset,null,null,&check);//Returns a readable monitor object if (Fd_isset (Stdin_fileno,&readset)) {//hypothesis           Monitoring to the 1 pipeline has standard input so get to the data written into the pipeline memset (buf,0,sizeof (BUF));           Fgets (Buf,sizeof (BUF), stdin);           Buf[strlen (BUF) -1]= ' + ';           Write (f1,buf,sizeof (BUF));//written to pipe 1} if (Fd_isset (F2,&readset)) {//Monitor to pipe 2 to read           memset (buf,0,sizeof (BUF)); Read (f2,buf,sizeof (BUF));//reads from pipeline 2 to buf strcpy (P->BUF,BUF);//The BUF read in pipeline 2 to the shared memory printf ("From 2:%s\          n ", buf);          } if (strcmp (buf, "Bye") ==0) {break; }} exit (0);}

b Process

#include <stdlib.h> #include <stdio.h> #include <string.h> #include <sys/shm.h> #include < sys/sem.h> #include <unistd.h> #include <sys/ipc.h> #include <sys/time.h> #include <fcntl.h > #include <sys/types.h> #include <sys/stat.h>int shm_id;struct t{char buf[128];};        struct T *p;void hanle (int sig) {SHMDT (P);        Shmctl (shm_id,ipc_rmid,null);//delete shared memory printf ("delete ok........\n"); Exit (0);}         int main () {//b process signal (SIGINT,HANLE); Shm_id=shmget ((key_t) 1235,4096,0600|        Ipc_creat);//struct T *p;        p= (struct t*) Shmat (shm_id,null,0);        int F1;     F1=open ("1.fifo", o_rdonly);//to 1 open read-end int f2;        F2=open ("2.fifo", o_wronly);//to 2 open write-end fd_set Readset;        Defines the readable set int maxfd; Maxfd=stdin_fileno > F1?        stdin_fileno+1:f1+1;        struct Timeval check;        check.tv_sec=1;//set viewing time is one second char buf[128]; while (1) {Fd_zero (& readset);//Initialize Fd_set (stdin_fileno,&readset);//Join the Monitoring Object Fd_set (F1,&readset); Select (Maxfd,&readset,null,null,&check);//Returns a readable monitor object if (Fd_isset (Stdin_fileno,&readset)) {//hypothesis           Monitoring to the 1 pipeline has standard input so get to the data written into the pipeline memset (buf,0,sizeof (BUF));           Fgets (Buf,sizeof (BUF), stdin);           Buf[strlen (BUF) -1]= ' + '; Write (f2,buf,sizeof (BUF));//written to Pipeline 2} if (Fd_isset (F1,&readset)) {///monitored to be able to read MEMS in Pipe 2           ET (buf,0,sizeof (BUF));          Read (f1,buf,sizeof (BUF));//reads strcpy (P-&GT;BUF,BUF) from pipe 1;//places the read-out characters into the shared memory printf ("From 1:%s\n", buf);          } if (strcmp (buf, "Bye") ==0) {break; }} exit (0);}

A1 Process

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/shm.h> #include < String.h>int shm_id;struct t{        char buf[128];}; struct T *p;void hanle (int sig) {        SHMDT (p);        Shmctl (shm_id,ipc_rmid,null);//delete shared memory        printf ("delete ok........\n");        Exit (0);} int main () {         shm_id=shmget (key_t) 1234,4096,0600| Ipc_creat);        Acquired shared memory//      struct T *p;        p= (struct t*) Shmat (shm_id,null,0);//This also got        char s[128]={0};        while (1)        {        if (strcmp (s,p->buf)!=0)        {//string is not the same  then print out        strcpy (S,P->BUF);        printf ("From B   :%s\n", p->buf);        }        }        Exit (0);}

B1 process

<span style= "FONT-SIZE:14PX;" > #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/shm.h> #include <string.h>int shm_id;struct t{        char buf[128];}; struct T *p;void hanle (int sig) {        SHMDT (p);        Shmctl (shm_id,ipc_rmid,null);//delete shared memory        printf ("delete ok........\n");        Exit (0);} int main () {         shm_id=shmget (key_t) 1235,4096,0600| Ipc_creat);        Acquired shared memory//      struct T *p;        p= (struct t*) Shmat (shm_id,null,0);//This also got        char s[128]={0};        while (1)        {        if (strcmp (s,p->buf)!=0)        {//string is not the same  then print out        strcpy (S,P->BUF);        printf ("From A   :%s\n", p->buf);        }        }        Exit (0);} </span><span style= "FONT-SIZE:18PX;" ></span>

Three: Results show

Code--QQ Chat implementation (based on the Linux pipeline Signal sharing memory)