Pipes problem.

[byteme101]

I have a logging process and 2 childen. The two children are suppose to use 1 pipe to send messages back to the parent. The problem I am having is that I am apparently sending the info at the same time. Is there a command like wait(&status) that I have to use in B before I write to the pipe again.

 


#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <time.h>

void cat(char times[]);

int main(void)
{

        int randomNumber;

        int child4[2];
        int child3[2];
        int tochild[2];
        int child2[2];

        char buffer[300];
        char buffer2[300];
        char buffer3[300];
        char buffer4[300];
        int status;
        int pid;
        int pid2;

        

        buffer[0]='\0';
        buffer2[0]='\0';
        buffer3[0]='\0';
        buffer4[0]='\0';



         pipe(tochild);
         pipe(child2);
        char *p=buffer;
        char *r=buffer3;
        if((pid=fork())==0)
        {
                int w=0;
                while(w<10)
                 {
                         char astring[3];
                         char message[20];
                         randomNumber=rand() %2;
                         if(randomNumber==0)
                         {
                                 astring[0]='D';
                                 astring[1]=w+48;
                                 astring[2]='\0';
                         }
                         if(randomNumber==1)
                         {
                                 astring[0]='c';
                                 astring[1]=w+48;
                                 astring[2]='\0';
                         }
                         strcat(buffer, astring);
                         
                         
                         strcpy(message, "A sends B  ");
                         strcat(message, astring);
                         strcat(buffer3, message);
                         w++;
                 }
                                 
                         

                close(child2[0]);

                while(*p)
                {

                        //if(rand() &1) sleep(1);

                        write(tochild[1], p++, 1);
                }
                close(tochild[1]);
                while(*r)
                {
                        write(child2[1],r++,1);
                }
                close(child2[1]);

                printf("returned to main");
                _exit(1);
        }



        int V=0;


        int pd=0;
        while(pd<10)
        {


                if((V=read(child2[0], buffer4, 13))==-1)
                {
                         perror("child failed");
                        _exit(1);
                }
                close(child2[0]);
                buffer4[13]='\0';
                char mytime[27];
                cat(mytime);
                strcat(buffer4, " ");
                strcat(buffer4, mytime);


                pd++;
                printf("%s\n", buffer4);
                 
        }


        //printf("%s\n", buffer4);

        sleep(15);

        int i;
        int p3[2];
        int p4[2];
         if((pid2=fork())==0)   //code for process B
        {
                int V;
                char Bstring[3];
                Bstring[0]='\0';
                pipe(p3);
                close(p3[0]);
                close(p3[0]);
                pipe(p4);
                close(p4[0]);
                char bstring[50];
                char cstring[50];
                char log[160];
                bstring[0]='\0';
                cstring[0]='\0';
                log[0]='\0';


                int atempvar=0;
                while(atempvar<10)
                {
                  

                 
                  if((V=read(tochild[0], Bstring, 2))==-1) 
                  {
                          printf("yuck");
                          _exit(1);
                  }
                  Bstring[2]='\0';

                  printf("%s\n", Bstring);
                  if(Bstring[0]=='c')
                  {
                          strcat(bstring, Bstring);
                          char message[20];
                          strcpy(message, "B SENDS C  ");
                          strcat(message, Bstring);
                           printf("%s\n", message);  //remove
                           
                  }

                  if(Bstring[0]=='D')
                  {
                          strcat(cstring, Bstring);
                          char message[20];
                          strcpy(message, "B sends D ");
                          strcat(message, Bstring);
                           printf("%s\n", message); //remove
                           
                  }
                  
                  
                  atempvar++;
                }
                char* bpointer= bstring;
                while(*bpointer)
                {
                        sleep(1);
                        write(p3[1], bpointer++, 1);
                }
                close(p3[1]);
                char* cpointer=cstring;
                while(*cpointer)
                {
                        sleep(1);
                        write(p4[1], cpointer++, 1);
                }
                close(p4[1]);
                close(child2[0]);
                char* logpointer = log;
                sleep(10);
                while(*logpointer)
                {
                        sleep(1);
                        write(child2[1], logpointer++, 1);
                }
                close(child2[1]);


        };

        //logging process

         int   ph=0;
         char logstream[150];
         logstream[0]='\0';
         if((ph=read(child2[0], logstream, 150))==-1)
         {
                 printf("error reading input from B");
                 return(1);
         }
        // printf("%s\n", logstream);



         return 0;
}

void cat(char  times[])
{
        char *timetoday;
        time_t rawtime;

        time(&rawtime);

        //printf("current data and time are %s\n", ctime(&rawtime));
        strcpy(times, ctime(&rawtime));
        return;

}