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Full Discussion: Problem with execution of fork system call if i use \n
Top Forums Programming Problem with execution of fork system call if i use \n Post 302483241 by Corona688 on Friday 24th of December 2010 03:27:57 PM
Old 12-24-2010
What happens is this:

Code:
// Without \n, this goes into a buffer and isn't printed yet.
printf("demo of fork");
// This creates a precise duplicate of the process -- including buffers.
// "demo of fork" will now be printed twice!
fork();
// this adds more stuff to the buffers of both programs.
printf("hello");
// The buffers will be flushed when the programs exit.  They may not exit
// in any particular order, and may try and print at the same time,
// causing the garble you see.

Code:
printf("demo of fork");
// Force it to print the buffer NOW, without waiting, so the child process
// doesn't get a copy of it in its own buffer.
fflush(stdout);
fork();
printf("hello");

This User Gave Thanks to Corona688 For This Post:
pnirmala
 

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LEARN ABOUT V7

fork

FORK(2) 							System Calls Manual							   FORK(2)

NAME

       fork  -	spawn new process

SYNOPSIS

       fork( )

DESCRIPTION

       Fork  is  the only way new processes are created.  The new process's core image is a copy of that of the caller of fork.  The only distinc-
       tion is the fact that the value returned in the old (parent) process contains the process ID of the new (child) process,  while	the  value
       returned in the child is 0.  Process ID's range from 1 to 30,000.  This process ID is used by wait(2).

       Files open before the fork are shared, and have a common read-write pointer.  In particular, this is the way that standard input and output
       files are passed and also how pipes are set up.

SEE ALSO

       wait(2), exec(2)

DIAGNOSTICS

       Returns -1 and fails to create a process if: there is inadequate swap space, the user is not super-user and has too many processes, or  the
       system's process table is full.	Only the super-user can take the last process-table slot.

ASSEMBLER

       (fork = 2.)
       sys fork
       (new process return)
       (old process return, new process ID in r0)

       The return locations in the old and new process differ by one word.  The C-bit is set in the old process if a new process could not be cre-
       ated.

																	   FORK(2)
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