Write a C program that illustrates two processes communicating using shared memory.
AIM:
Write a C program that illustrates two processes communicating using shared memory.
Program:
#include<stdio.h> #include<sys/types.h> #include<sys/ipc.h> #include<sys/shm.h> Struct country { Char name[30]; Char capital_city [30]; Char currency[30]; Int population; }; Int main(int argc,char*argv[]) { Int shm_id; Char*shm_addr; Int*countries_num; Struct country*countries; Struct shmid_ds shm_desc; Shm_id=shmget(100,2048,IPC_CREAT|IPC_EXCL\0600); If(shm_id==-1){ Perror(“main:shmget:”); Exit(1); } Shm_addr=shmat(shm_id,NULL,0); If(!shm_addr){ Perror(“main:shmat:”); Exit(1); } Countries_num=(int*)shm_addr; *countries_num=0; Countries=(struct country*)((void*)shm_addr sizeof(int)); Strcpy(countries[0],name,”U.S.A”); Strcpy(countries[0],capital_city,”WASHINGTON”); Strcpy(countries[0],currency,”U.S.DOLLAR”); Countries[0].population=250000000; ( countries_num) ; Strcpy(countries[1].name,”israel”); Strcpy(countries[1].capital_city,”jerushalem”); Strcpy(countries[1].currency,”NEW ISRAEL SHEKED”); Countries[1].population=6000000; (*countries_num) ; Strcpy(countries[2].name,”France”); Strcpy(countries[2].capital_city,”paris”); Strcpy(countries[2].currency,”Frank”); Countries[2].population=60000000; (*countries_num) ; For(i=0;i<(*countries_num);i ) { Printf(“country%d:\n”,i 1); Printf(“name:%d:\n”,i 1); Printf(“currency:%s:\n”,countries[i].currency); Printf(“population:%d:\n”,countries[i].population); } If(shmdt(shm_addr)==-1){ Perror(“main:shmdt:”); } If(shmctl(shm_id,IPC_RMID,&SHM_DESC)==-1) { Perror(“main:shmctl:”); } return 0; }
Output:
Student@ubuntu:~$gcc shm.c
Student@ubuntu:~$ ./a.out
Shared memory ID=65537 child pointer 3086680064
Child value =1
Shared memory ID=65537 child pointer 3086680064
Parent value=1
Parent value=42
Child value=42
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UpdatedOct 23, 2014
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Views17,722
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