c - why return in if and else not working -

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i have simple doubt. trying 2 processes comm using named pipes. it's working fine press n ans, it's not executing return of main. printing "received child : " in parent process.

#include<stdio.h> #include<stdlib.h> #include<unistd.h> #include <errno.h> #include <fcntl.h> #include <sys/stat.h> #include<string.h> #include<ctype.h> #include<wait.h> #define np1 "/tmp/np1" #define np2 "/tmp/np2" #define max_buf_size    255 #include <sys/types.h>  int main() {     int rdfd, wrfd, ret_val, count, numread;     char buf[max_buf_size];     char ans;     char cp[50];     pid_t pid;      ret_val = mkfifo(np1,0666);     if ((ret_val == -1) && (errno != eexist)) {         perror("error creating named pipe");         exit (1);     }     ret_val = mkfifo(np2, 0666);     if ((ret_val == -1) && (errno != eexist)) {         perror("error creating named pipe");         exit (1);     }     printf("\nsend parent process\t");     scanf("%[^\n]%*c",&ans);      pid=fork();     if (pid==-1) {         printf("\nerror in pid");         exit(1);     }     while (ans=='y' || ans=='y') {         if (pid!=0) {             //parent process             /* open first named pipe reading */             rdfd = open(np1, o_rdonly);             numread = read(rdfd, buf, max_buf_size);             buf[numread] = '\0';             printf("received child : %s\n", buf);              /* convert string upper case */             count = 0;             while (count < numread) {                 buf[count] = toupper(buf[count]);                 count++;             }              wrfd = open(np2, o_wronly);              /* write converted string second pipe */             write(wrfd, buf, strlen(buf));         } else {             //child process             printf("\nenter data sent parent\t");             fgets(cp, 50, stdin);             wrfd = open(np1, o_wronly);             /* write pipe */             write(wrfd, cp, strlen(cp)+1);             /* open second named pipe reading */             rdfd = open(np2, o_rdonly);             /* read pipe */             numread = read(rdfd, buf, max_buf_size);             buf[numread] = '\0';             printf("received parent : %s\n", buf);             printf("\nsend parent process\t");             fflush(stdin);             scanf(" %[^\n]%*c",&ans);         }     }      return 0; }

the problem code when u give n input child, parent still alive in order kill parent use return read in parent see if child has exited or not , if child exit, exit parent too. can done editing code with
if( (numread = read(rdfd, buf, max_buf_size)) == 0) return 0;

actually once give n input in child, child exits , old value of ans y compared in parent process , doesn't exit....

check n reply... thanks...


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