On 2007-09-23 11:02, Bhavin wrote:
> HI,
> I have to implement a program using exec command to illustrate
> concurrent and sequential process. What I did is just create two input
> file
>
> Alpha.txt
> ========
> abcdefghijklmnopqrstuvwxyz
> abcdefghijklmnopqrstuvwxyz
> abcdefghijklmnopqrstuvwxyz
> abcdefghijklmnopqrstuvwxyz
> abcdefghijklmnopqrstuvwxyz
> . . .
> abcdefghijklmnopqrstuvwxyz (upto 50 lines)
>
> Number.txt
> ========
> 1234567890
> 1234567890
> 1234567890
> . . .
> 1234567890 ( upto 50 lines)
>
>
> my code is
> ========
> #include <sys/types.h>
> #include<unistd.h>
> #include<iostream>
>
> using namespace std;
>
> int pid1,pid2;
>
> int main ()
> {
>
> pid1 = fork(); //first child process
>
> if (pid1<0){
>
> perror("error");
>
> }
>
> if (pid1 ==0)
> {
>
> execl("/bin/cat","cat","Alpha.txt",NULL);
>
> }
> //parent process
>
> if (pid1>0) {
>
> }
>
> pid2 =fork(); //second child process
>
> if (pid2==0){
>
> execl("/bin/cat", "cat","Number.txt",NULL);
> }
>
> if (pid2>0){
>
>
> }
> }
>
>
> output ( I want output in this manner)
> ===========================
> For Concurrent process:-
>
> abcdefghijklmnopqrstuvwxyz
> 1234567890
> abcdefghijklmnopqrstuvwxyz
> 1234567890
> abcdefghijklmnopqrstuvwxyz
> abcdefghijklmnopqrstuvwxyz
> 1234567890
> ..................... ( this its goes one)
>
> but i am getting all the alphabets first then number( they are not
> overlapping which it should happened in concurrent)
>
>
> For Sequential process :
>
> I want all alphabets then number
>
> please help me, Thanks in advance


First of, you are off topic in this group since what you are using and
seeing are platform specific. Your problem is that your files are quite
small and the scheduler does not have time to make a process switch
before the fist cat has finished (I'm not sure but I think many
schedulers give new processes a bit of extra time). I think the best
solution would be to make the files much larger, 500 or 5000 lines and
redirect the output to a file (beware of file locking).

--
Erik Wikström