Question

Rewrite the program as a set of two programs that utilize a named pipe “ages” in the current folder for IPC and implement the same function as discussed above.

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <sys/types.h>

int main(void)

{

        int     fd[2], nbytes;

        pid_t   childpid;

        int users = 95;

        char mystring[80];

        char    readbuffer[80];

        char digit1,digit2;

        digit1 = (char) users%10;

        digit2 = (char ) users/10;

        mystring[0] = digit1;

        mystring[1] = digit2;

        printf("%d %d\n",mystring[0],mystring[1]);

        pipe(fd);

        if((childpid = fork()) == -1)

        {

                perror("fork");

                exit(1);

        }

        if(childpid == 0)

        {

                /* Child process closes up input side of pipe */

                close(fd[0]);

                /* Send "string" through the output side of pipe */

                write(fd[1], mystring, sizeof(mystring));

                exit(0);

        }

        else

        {

                /* Parent process closes up output side of pipe */

                close(fd[1]);

                /* Read in a string from the pipe */

                nbytes = read(fd[0], readbuffer, sizeof(readbuffer));

                printf("Received string: %d %d\n",readbuffer[0],readbuffer[1]);

        }

}

Answer 1

// C program to implement one side of FIFO
// This side writes
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

int main()
{
   int fd;
int users = 95;
char mystring[80];
char digit1,digit2;
digit1 = (char) users%10;
digit2 = (char ) users/10;
mystring[0] = digit1;
mystring[1] = digit2;
mknod("/ages", S_IFIFO|0666, 0); // Creating the named file(FIFO)
fd = open(myfifo, O_WRONLY); // Open FIFO for write only
write(fd,mystring,sizeof(mystring));
   close(fd);
   return 0;
}
.

.

// C program to implement second side of FIFO
// This side reads
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

int main()
{
   int fd;
char readbuffer[80];
fd = open("/ages",O_RDONLY); // Open FIFO for read only
read(fd,readbuffer,sizeof(readbuffer));
printf("Received string: %d %d\n",readbuffer[0],readbuffer[1]);
   close(fd);
   return 0;
}