08-30-2012
The only way to do this is by sharing file descriptors using UNIX domain sockets.
Here is sample code, from several years ago:
Unix socket magic
This User Gave Thanks to jim mcnamara For This Post:
10 More Discussions You Might Find Interesting
1. HP-UX
Hi, i'd like to get the files which are opened by a process during his execution using the c language.
Thanks for helping me. (2 Replies)
Discussion started by: benoit.gaillard
2 Replies
2. Programming
Hi All,
We can find the maximum of open file descriptors in hold with respect to a process.
As default size was 256 (with getrlimit) and the hard limt was 65536
I tried changing the limit to 1024(with setrlimit)
successfully changed the limit
but still I couldnt have as many open file... (3 Replies)
Discussion started by: matrixmadhan
3 Replies
3. Shell Programming and Scripting
Is there a way to tell for sure if a file currently is opened by any running process?
I have a task to filter a text file which is produced by some long process.
I have no way to communicate with that process, but I have access to a location, where that proces produce an output file.
Need... (3 Replies)
Discussion started by: alex_5161
3 Replies
4. UNIX for Advanced & Expert Users
I want to avoid a situation where because two users simultaneously
open a file and modify and save, leaving the original file in mess.
Is there a way in UNIX to warn a user if that particular file is already being
used by another user.
Thanks in advance (3 Replies)
Discussion started by: paresh n doshi
3 Replies
5. Shell Programming and Scripting
Hello all,
I have a file that is growing and growing by the action of any process.
How can I find what process is?
Thank you (2 Replies)
Discussion started by: albertogarcia
2 Replies
6. Shell Programming and Scripting
Hi *,
I'm wondering if it possible to know WHO opened or modified a file last?
I know it's possible with some options of find and also ls to get when the file was modified last.
I'm currently supervising a file and have to log all users name who opened or modified it.
Thanx a lot for any... (3 Replies)
Discussion started by: Jabarod
3 Replies
7. Shell Programming and Scripting
I am writing a shell script (runs on HP Unix) which copies files from a source directory to another destination daily. The destination directory always have the files with same name as in the source directory. And daily a new file will be created in the source.
cp command works fine if the file... (1 Reply)
Discussion started by: arunkumar_ms
1 Replies
8. AIX
Hi,
How to release file description area from specified process.
Problem is that process started - open one file ( ~2GB ) - file has been removed - process still shown that file is used by process and can't release space on filesystem.
It is not allowable to kill process !!!
Regs,... (3 Replies)
Discussion started by: KrzysiekPi
3 Replies
9. Shell Programming and Scripting
Hi
#Testing for file existence
if ; then
echo 'SCHOOL data is available for processing'
else
echo 'SCHOOL DATA IS NOT AVAILABLE FOR PROCESSING'
:
i wrote a script, where it begins by checking if file exists or not.
If it exists, it truncates the database... (2 Replies)
Discussion started by: rxg
2 Replies
10. UNIX for Advanced & Expert Users
Can any help me in finding the way to close opened file descriptor in Solaris ,without killing process. As accidently a file was removed which was opened by a process.
Much thanks in advance :) (11 Replies)
Discussion started by: nitj
11 Replies
DUP(2) BSD System Calls Manual DUP(2)
NAME
dup, dup2 -- duplicate an existing file descriptor
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
dup(int oldd);
int
dup2(int oldd, int newd);
DESCRIPTION
The dup() system call duplicates an existing object descriptor and returns its value to the calling process (newd = dup(oldd)). The argument
oldd is a small non-negative integer index in the per-process descriptor table. The new descriptor returned by the call is the lowest num-
bered descriptor currently not in use by the process.
The object referenced by the descriptor does not distinguish between oldd and newd in any way. Thus if newd and oldd are duplicate refer-
ences to an open file, read(2), write(2) and lseek(2) calls all move a single pointer into the file, and append mode, non-blocking I/O and
asynchronous I/O options are shared between the references. If a separate pointer into the file is desired, a different object reference to
the file must be obtained by issuing an additional open(2) system call. The close-on-exec flag on the new file descriptor is unset.
In dup2(), the value of the new descriptor newd is specified. If this descriptor is already in use and oldd != newd, the descriptor is first
deallocated as if the close(2) system call had been used. If oldd is not a valid descriptor, then newd is not closed. If oldd == newd and
oldd is a valid descriptor, then dup2() is successful, and does nothing.
RETURN VALUES
These calls return the new file descriptor if successful; otherwise the value -1 is returned and the external variable errno is set to indi-
cate the cause of the error.
ERRORS
The dup() system call fails if:
[EBADF] The oldd argument is not a valid active descriptor
[EMFILE] Too many descriptors are active.
The dup2() system call fails if:
[EBADF] The oldd argument is not a valid active descriptor or the newd argument is negative or exceeds the maximum allowable
descriptor number
SEE ALSO
accept(2), close(2), fcntl(2), getdtablesize(2), open(2), pipe(2), socket(2), socketpair(2), dup3(3)
STANDARDS
The dup() and dup2() system calls are expected to conform to ISO/IEC 9945-1:1990 (``POSIX.1'').
HISTORY
The dup() and dup2() functions appeared in Version 7 AT&T UNIX.
BSD
June 1, 2013 BSD