fork() printf file redirection

[dresden0526]

I am a little confused right now.

I have some code that

#include <stdio.h>

#include <stdlib.h>

main ()

{

int k;

printf ("Main Process' PID = %d\n", getpid());

fflush(stdout);

for (k = 1; k <= 3; k++)

{

fork ();

printf ("k = %d, PPID = %d, pID = %d, I'm Alive!\n", k, getppid(), getpid());

fflush(stdout);

}

}

When I run the program to the terminal I get

k =1, PPID =25078, pID =25079. I'm Alive!

k =1, PPID =25034, pID =25078. I'm Alive!

k =2, PPID =25078, pID =25079. I'm Alive!

k =2, PPID =25034, pID =25078. I'm Alive!

k =3, PPID =25078, pID =25082. I'm Alive!

k =3, PPID =25034, pID =25078. I'm Alive!

k =2, PPID =25078, pID =25081. I'm Alive!

k =3, PPID =1, pID =25079. I'm Alive!

k =3, PPID =25079, pID =25083. I'm Alive!

k =2, PPID =25079, pID =25080. I'm Alive!

k =3, PPID =25081, pID =25084. I'm Alive!

k =3, PPID =25080, pID =25085. I'm Alive!

k =3, PPID =1, pID =25081. I'm Alive!

k =3, PPID =1, pID =25080. I'm Alive!

Which is what I expected when I run this code, becuase fork creates a child process that inherits the buffer from the parent, so when I flush it the printf statement is flushed to the terminal and the I'm alive statement is printed.

What I am consued about is when I redirect the output

when I run ./a.out > file

I get :

Main Process' PID =25209

k =1, PPID =25161, pID =25209. I'm Alive!

k =2, PPID =25161, pID =25209. I'm Alive!

k =3, PPID =25161, pID =25209. I'm Alive!

What is heppening when I redirect the file?

[alf55]

The redirection is handled by the shell and not by the program, so the children do not inherit the redirection.