UNIX for Dummies Questions & Answers

#include <stdlib.h>
#include <string.h>
#include <stdio.h>    /* standard I/O routines.                */
#include <unistd.h>   /* defines pipe(), amongst other things. */

#define ARRAY_SIZE 1000

int main(int argc, char* argv[])
{
    int data_pipe[2];
    int pid;
    int i = 0;
    char readbuffer[ARRAY_SIZE];
    char *in_str; /*= argv[1];*/

    for(i = 0; i < sizeof(readbuffer); i++)
        readbuffer[i] = 0;

    for(i = 1; i < argc; i++)
    {
        if(i > 1)
        {
            argv[i] = strncat(argv[i - 1],argv[i],1000);
        }
    }

    if(argc > 1)
        in_str = argv[i - 1];

    //printf("Printing string: %s\n", argv[i - 1]);
    //printf("The sentence entered is %u characters long.\n",strlen(argv[i - 1]));

    /* first, create a pipe. */
    pipe(data_pipe);

    /* now fork off a child process, and set their handling routines. */
    pid = fork();

    if(pid == -1)       /* fork failed. */
    {
        perror("fork");
        exit(1);
    }
    else if(pid == 0)           /* inside child process. */
    {
        close(data_pipe[1]);
        read(data_pipe[0], readbuffer, sizeof(readbuffer));
        printf("child: counted %d characters\n", strlen(readbuffer));

        //for(i = 0; i < 30; i++)
        //      printf("%d:  %c\n", i, readbuffer[i]);
        //printf("Received String: %s\n", readbuffer);
        sleep(5);
        exit(0);
    }
    else /* inside parent process */
    {
        close(data_pipe[0]);
        while (*in_str != '\0')
        {
            in_str++;
            write(data_pipe[1], &in_str, 1);
        }
        exit (0);
    }

    return 0;
}