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Full Discussion: Regaring File Table entry
Operating Systems Linux Fedora Regaring File Table entry Post 302394637 by darshan.ghumare on Friday 12th of February 2010 06:20:55 AM
Old 02-12-2010
Regaring File Table entry
Hi,

I have written following code & ran it on Fedora Linux.
Before executing it I have created a.txt (touch a.txt).

Code:
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>

int main()
{
    int fd1, rc;

    fd1 = open("a.txt", O_WRONLY);
    if (fd1 == -1)
    {
        printf("Open error\n");
        return -1;
    }
    write(fd1, "ABCD", 4);
    if (fork() > 0)
    {
        write(fd1, "XYZ", 3);
        return 0;
    }
    wait(&rc);
    write(fd1, "EFGH", 4);
    return 0;
}

Why contents of a.txt are "ABCDXYZEFGH"?
More precisely, why kernel had not created separate entry in File Table for child process?
What is the reason behind sharing of File Table entry between parent & child process?
I think as child is independent process. Then if it has written at offset 10 then offset will be incremented to 11 but parent offset should remain at 10 only.
 

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LEARN ABOUT DEBIAN

ecaccess-file-move

ECACCESS-FILE-MOVE(1p)					User Contributed Perl Documentation				    ECACCESS-FILE-MOVE(1p)

NAME

       ecaccess-file-move - Move or Rename ECaccess Files

SYNOPSIS

       ecaccess-file-move -version|-help|-manual

       ecaccess-file-move [-debug] source-ecaccess-file target-ecaccess-file

DESCRIPTION

       Allow moving an ECaccess File. When the move occurs within the same ECaccess File System then it is a rename. When the move occurs across
       two different ECaccess File Systems then first a copy is done and then a delete of the original file is done (e.g. similar to ecaccess-
       file-copy ... -erase).

       The source-ecaccess-file and target-ecaccess-file are in the form [domain:][/user-id/]path. Please read the "Shell commands -> File
       Management" section of the "ecaccess" guide for more information on the ECaccess File System.

ARGUMENTS

       source-ecaccess-file
	       The source ECaccess File name.

       target-ecaccess-file
	       The target ECaccess File name.

OPTIONS

       -version
	       Display version number and exits.

       -help   Print a brief help message and exits.

       -manual Prints the manual page and exits.

       -debug  Display the SOAP messages exchanged.

EXAMPLES

       ecaccess-file-move ec:test1.txt ec:test2.txt

       Rename the test1.txt file in the ECFS directory of the authenticated user in test2.txt.

       ecaccess-file-move ec:test1.txt home:test2.txt

       Copy the test1.txt file from the ECFS directory of the authenticated user to the test2.txt file in the $HOME directory of the authenticated
       user, then delete the test1.txt file from ECFS.

SEE ALSO

       ecaccess-file-delete, ecaccess-file-get, ecaccess-file-mget, ecaccess-file-modtime, ecaccess-file-mput, ecaccess-file-rmdir, ecaccess-file-
       copy, ecaccess-file-dir, ecaccess-file-mdelete, ecaccess-file-mkdir, ecaccess-file-chmod, ecaccess-file-put, ecaccess-file-size and
       ecaccess.

perl v5.14.2							    2012-04-16						    ECACCESS-FILE-MOVE(1p)
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