03-11-2010
Difference between file descriptor and file pointer
hi....,
can anyone tell me what is the exact difference between file descriptor and file pointer...... and why file descriptor takes integer value???
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
I am trying to find a way to check the current status of a file. Such as some cron job processes are dependent on the completion of others. if a file is currently being accessed / modified or simply open state I will wait until it is done being processed before attempting the next process on that... (3 Replies)
Discussion started by: Gary Dunn
3 Replies
2. UNIX for Dummies Questions & Answers
What is a file descriptor in Unix??
How to find a file descriptor of a file in Unix??
Does it have anything to do with the Inode numbers?? (3 Replies)
Discussion started by: rahulrathod
3 Replies
3. UNIX for Dummies Questions & Answers
Hi everybody,
i am newbie to unix and confused with file pointers and file descripters.
could anyone help me to clear my doubts ..
when we call unix system calls to create a file then we are dealing wih file descripters
i think file descripters are also normals file as stored inhard disks... (1 Reply)
Discussion started by: johnray31
1 Replies
4. Programming
Hi,
I want to validate that a file is a socket file on Linux. I know I can do this using the S_ISSOCK macro, but I am not sure how to get the file descriptor for the socket file.
For example, I know that /tmp/mapping-foo is a socket file. In Python I can do something like this:
>>> import... (2 Replies)
Discussion started by: goon12
2 Replies
5. Shell Programming and Scripting
Hello All,
Im opening a file desciptor in perl and sending data using print CMD "$xyz".
is there a limit to the length of the string that I can give to this CMD at a time. (3 Replies)
Discussion started by: rimser9
3 Replies
6. UNIX for Dummies Questions & Answers
Hi
What the below path contains?
/proc/<pid>/fd (1 Reply)
Discussion started by: siba.s.nayak
1 Replies
7. Programming
Hi ,
i have two basic requirement on linux platform . I am using C language to do this .
1) copying one file to another (assuming i know their file descriptors)
2) Overwriting a file using it file descriptor .
Please guide.
regards
Aki (2 Replies)
Discussion started by: meet123321
2 Replies
8. Shell Programming and Scripting
Hello,
How can i use file descriptor in a script to read 2 files at the same time and extract line 200 from file 1 and line 500 from file 2.
Thanks. (6 Replies)
Discussion started by: LiorAmitai
6 Replies
9. Shell Programming and Scripting
I am trying to write a script which will only show me the file descriptor count for a process/pid. My script will return me the count only not the whole output. For example, I would like my script to return the output 23 this case, not the whole output.
Can anybody please help me how do I get... (11 Replies)
Discussion started by: mohullah
11 Replies
10. Shell Programming and Scripting
Greetings.
I am happily using constructs like the following; I have set -x to show fine distinctions.
$ exec 4> afile
+ exec
+ 4> afile
$ print -u4 This is the first line in afileAs you can see from the -x expansion, the shell performed the exec command and redirected file descriptor to... (4 Replies)
Discussion started by: rpaskudniak
4 Replies
dup(2) System Calls Manual dup(2)
NAME
dup - duplicate an open file descriptor
SYNOPSIS
DESCRIPTION
fildes is a file descriptor obtained from a or system call. returns a new file descriptor having the following in common with the origi-
nal:
o Same open file (or pipe).
o Same file pointer (i.e., both file descriptors share one file pointer).
o Same access mode (read, write or read/write).
o Same file status flags (see fcntl(2),
The new file descriptor is set to remain open across system calls. See fcntl(2).
The file descriptor returned is the lowest one available.
RETURN VALUE
Upon successful completion, the file descriptor is returned as a non-negative integer. Otherwise, a value of -1 is returned and is set to
indicate the error.
ERRORS
fails if one or more of the following is true:
fildes is not a valid open file descriptor.
Request violates the maximum number of open file descriptors.
AUTHOR
was developed by AT&T and HP.
SEE ALSO
close(2), creat(2), dup2(2), exec(2), fcntl(2), open(2), pipe(2), privileges(5).
STANDARDS CONFORMANCE
dup(2)