On Aug 21, 10:44*am, Shashank wrote:
> This is a program which I wrote. Please help me identifying the error
> or suggest the alternative solution.
>
> #include
> #include
> #include
>
> int main()
> {
> * * * * FILE *fp1, *fp2;
> * * * * int fd[2],i;
> * * * * char ch;
> * * * * fp1 = fopen("input", "r");
> * * * * fp2 = fopen("output","w");
>
> * * * * if(pipe(fd)<0)
> * * * * * * * * exit(1);
>
> * * * * //while(1)
> * * * * for(i =0; i<54; i++)
> * * * * {
> * * * * if(fork()==0)

Why are you forking 54 times?

> * * * * {
> * * * * * * close(fd[0]);
> * * * * * * if((ch=fgetc(fp1))==EOF) break;
> * * * * * * write(fd[1], &ch, 1 );
> * * * * }
> * * * * else
> * * * * {
> * * * * * * close(fd[1]);
> * * * * * * read(fd[0], &ch, 1 );
> * * * * * * fputc(ch, fp2);
> * * * * }
> * * }
>
> * * fclose(fp1);
> * * fclose(fp2);
>
>
>
> }
>

What are you trying to do? What did you expect this program to do?
What does it actually do? What is the "error" you say is happening?
--
Fred Kleinschmidt

On 21 Aug, 18:44, Shashank wrote:
> This is a program which I wrote. Please help me identifying the error
> or suggest the alternative solution.
>
> #include
> #include
> #include
>
> int main()
> {
> * * * * FILE *fp1, *fp2;
> * * * * int fd[2],i;
> * * * * char ch;
> * * * * fp1 = fopen("input", "r");
> * * * * fp2 = fopen("output","w");
>
> * * * * if(pipe(fd)<0)
> * * * * * * * * exit(1);
>
> * * * * //while(1)
> * * * * for(i =0; i<54; i++)
> * * * * {
> * * * * if(fork()==0)
> * * * * {
> * * * * * * close(fd[0]);
> * * * * * * if((ch=fgetc(fp1))==EOF) break;
> * * * * * * write(fd[1], &ch, 1 );
> * * * * }
> * * * * else
> * * * * {
> * * * * * * close(fd[1]);
> * * * * * * read(fd[0], &ch, 1 );
> * * * * * * fputc(ch, fp2);
> * * * * }
> * * }
>
> * * fclose(fp1);
> * * fclose(fp2);
>
> }

First time through the loop, the parent closes fd[ 0 ]. The second
time in the loop, the new child is attempting to read from
that closed pipe.

What exactly are you trying to do?

On Aug 21, 11:17*am, Fred wrote:

> Why are you forking 54 times?

He's forking a lot more than 54 times! It would take the known age of
the universe for this program to complete all the forking it tries to
do.

DS

William Pursell writes:
>On 21 Aug, 18:44, Shashank wrote:
>> This is a program which I wrote. Please help me identifying the error
>> or suggest the alternative solution.
>>
>> #include
>> #include
>> #include
>>
>> int main()
>> {
>> =A0 =A0 =A0 =A0 FILE *fp1, *fp2;
>> =A0 =A0 =A0 =A0 int fd[2],i;
>> =A0 =A0 =A0 =A0 char ch;
>> =A0 =A0 =A0 =A0 fp1 =3D fopen("input", "r");
>> =A0 =A0 =A0 =A0 fp2 =3D fopen("output","w");
>>
>> =A0 =A0 =A0 =A0 if(pipe(fd)<0)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 exit(1);
>>
>> =A0 =A0 =A0 =A0 //while(1)
>> =A0 =A0 =A0 =A0 for(i =3D0; i<54; i++)
>> =A0 =A0 =A0 =A0 {
>> =A0 =A0 =A0 =A0 if(fork()=3D=3D0)
>> =A0 =A0 =A0 =A0 {
>> =A0 =A0 =A0 =A0 =A0 =A0 close(fd[0]);
>> =A0 =A0 =A0 =A0 =A0 =A0 if((ch=3Dfgetc(fp1))=3D=3DEOF) break;
>> =A0 =A0 =A0 =A0 =A0 =A0 write(fd[1], &ch, 1 );
>> =A0 =A0 =A0 =A0 }
>> =A0 =A0 =A0 =A0 else
>> =A0 =A0 =A0 =A0 {
>> =A0 =A0 =A0 =A0 =A0 =A0 close(fd[1]);
>> =A0 =A0 =A0 =A0 =A0 =A0 read(fd[0], &ch, 1 );
>> =A0 =A0 =A0 =A0 =A0 =A0 fputc(ch, fp2);
>> =A0 =A0 =A0 =A0 }
>> =A0 =A0 }
>>
>> =A0 =A0 fclose(fp1);
>> =A0 =A0 fclose(fp2);
>>
>> }
>
>First time through the loop, the parent closes fd[ 0 ]. The second
>time in the loop, the new child is attempting to read from
>that closed pipe.
>
>What exactly are you trying to do?

Not to mention the fork in (originally) a 'while(1)' loop. Can you say fork bomb?

s