READING 3 WRITERS WRITING IN SAME INSTANCE IN FAST FOR LOOP

/* 2nd writer*/

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<sys/ipc.h>

#include<unistd.h>

#include<sys/types.h>

int main()

{

        int ret,wfd,count=0;

        int buff=2;

        int a=4;

        int b=6;

        ret=mkfifo("anu",777|IPC_CREAT);

        if(ret==0)

                printf("fifo created\n");

        wfd=open("anu",O_WRONLY);//after
opening ...if it finds a reader...it will write data to fifo untill its
limit exceeds ...when limit came...it will allow reader to read ...then
again starts wriiting to fifo..

        printf("wfd=%d\n",wfd);

        count=write(wfd,&buff,4);

        printf("count=%d\nbuff=%d\n",count,buff);

        //fd=open("anu",O_WRONLY);

        //printf("fd=%d\n",fd);

        close(wfd);

        wfd=open("anu",O_WRONLY);//same reader will works for no. of writers

        printf("wfd=%d\n",wfd);

        count=write(wfd,&a,4);

        printf("count=%d\na=%d\n",count,a);

        close(wfd);//it will make no diffrence if i opened same fifo after closing....data will remain in that fifo......

        wfd=open("anu",O_WRONLY);

        printf("wfd=%d\n",wfd);

        count=write(wfd,&b,4);

        printf("count=%d\nb=%d\n",count,b);

        close(wfd);

        sleep(1);

        return 0;//once
writer process is terminated & means reader will not be able to
read...data from fifo will be erased ....& then again it opens
demands a reader to read to come out of block on open position

}

/*   LAST & WONDERFUL.....READING IN FOR LOOP TO ALL 3 THREE WRITERS IN SYNCHRONISED WAY */

/Every new process reader is for new process writer ......it does not matters either i m opening fifo..... again & again after closing wfd....in one process ...to read data by executing another program no. of times....means every time new reader of process will demand a new writer of process ..

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<unistd.h>

int main()

{

//sleep(2);

int i=0,fd;

int count,buf,a,b;

for(i=1;i<4;i++)

{

printf("**********i=%d**********\n",i);

fd=open("anu",O_RDONLY);//when both writer & reader r executing ...untill then ...reader can read the written data......otherwise again operating same reader will demand new writer ...that shold open now..& start wriiting data freshly...

printf("fd=%d\n",fd);

read(fd,&buf,4);//reader is able to read only upto the time in millisecond...untill there is writer..& no writting program or process is finished.....if i had made delay of 1 sec at staring of the this reader....untill then writer completes its work..& finished...no wait by writer untill fifo is full...then after that data will not be read....writer should be there if u want to read data from fifo....

printf("buf=%d\n",buf);

count=read(fd,&a,4);

printf("a=%d\n",a);

printf("count=%d\n",count);

printf("count=%d\n",count);

count=read(fd,&b,4);

printf("b=%d\n",b);

printf("count=%d\n",count);

//sleep(1);

}

return 0;

}