04-11-2009
I try to change the code from while(..) to do{.. } while(..) .. it works..
do
{
c[0]=fgetc(fin); // get each character from inputfile
write(fd[1],c,2); // write to pipe
}
while(c[0]!=EOF)
and it's work.. but wrong result.. Because the last c[0] = EOF, it is written to pipe, then while loop check the codition.. ( wrong ofcourse)..
I include if statement like this:
if(c[0]!= EOF)
{
c[0]=fgetc(fin);// get each character from inputfile
write(fd[1],c,2); // write to pipe
}
Problem again.. The output is blank.. so crazy.. please help me..
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
I have a parent that is passing data to child A and then child A has to process it and pass to child B. I am able to pass the data to child A but am not able to pass it to child B. Child B seems to only be receiving the last data instead of the whole data.
I saw one example in a book but it uses... (1 Reply)
Discussion started by: scmay
1 Replies
2. UNIX for Advanced & Expert Users
Hi All,
I am facing a vague issue while trying to make two process talk to each
other using named pipe.
read process
=========
The process which reads, basically creates FIFO using
mkfifo - ret_val = mkfifo(HALF_DUPLEX, 0666);) func.
It then opens the pipe using open func - fd =... (1 Reply)
Discussion started by: sharanbr
1 Replies
3. Programming
Hi All,
I am facing a vague issue while trying to make two process talk to each
other using named pipe.
read process
=========
The process which reads, basically creates FIFO using
mkfifo - ret_val = mkfifo(HALF_DUPLEX, 0666) func.
It then opens the pipe using open func - fd = open... (2 Replies)
Discussion started by: sharanbr
2 Replies
4. Solaris
I was asked to look into a problem with a Sun Netra 440 in another department. On the server in question, the relevant 'uname -a' information is, "SunOS host1 5.9 Generic_118558-16 sun4u sparc SUNW,Netra-440". That information aside, while the other admin is logged into the ALOM, these errors are... (0 Replies)
Discussion started by: Borealis
0 Replies
5. Programming
Hi!
I wanted to know the advantages / disadvantages of different IPC mechanims such as sockets, pipes (unnamed) , shared memory & message queues.
Pipes for example i hear are fast , but are difficult to debug as compared to sockets.
Can you guys please name some situations where one is... (4 Replies)
Discussion started by: _korg
4 Replies
6. Shell Programming and Scripting
Hi All ,
Is there any way to replace the pipe ( | ) with the broken pipe (0xA6) in unix (1 Reply)
Discussion started by: saj
1 Replies
7. Programming
Suppose I have 5 independent process divided in two imaginay sets:
set1 set2
---------------------
p1 p3
| |
p2 p4
|
p5
The processes inside each set communicate mutually quite often.
I mean p1 and p2 communicate mutually quite often
Similarly p3, p4 and p5 communicate mutually... (2 Replies)
Discussion started by: rupeshkp728
2 Replies
8. HP-UX
Hi Experts,
Need your help for checking te interprocess communications settings on HP-UX box.
Using ipcs command I am able to view Message queue,semapohores etc, but from that output I m not able to understand how to determine if there is any issue with ipc settings and how to resolve that? (1 Reply)
Discussion started by: sai_2507
1 Replies
9. Programming
I'm currently studying IPC, I have a first program
A: Do an exec for B and wait
B: Receive through a fifo a string from a third program "C" and have to resend it to A
I was thinking to open a pipe in A before the exec, then passing fd to B as an argument
if(pipe(fd)==-1){
... (1 Reply)
Discussion started by: cifz
1 Replies
10. Shell Programming and Scripting
Hi guys,
I need to know how i can ignore Pipe '|' if Pipe is coming as a column in Pipe delimited file
for eg:
file 1:
xx|yy|"xyz|zzz"|zzz|12...
using below awk command
awk 'BEGIN {FS=OFS="|" } print $3
i would get xyz
But i want as :
xyz|zzz to consider as whole column... (13 Replies)
Discussion started by: rohit_shinez
13 Replies
PIPE(2) System Calls Manual PIPE(2)
NAME
pipe - create an interprocess channel
SYNOPSIS
pipe(fildes)
int fildes[2];
DESCRIPTION
The pipe system call creates an I/O mechanism called a pipe. The file descriptors returned can be used in read and write operations. When
the pipe is written using the descriptor fildes[1] up to 4096 bytes of data are buffered before the writing process is suspended. A read
using the descriptor fildes[0] will pick up the data. Writes with a count of 4096 bytes or less are atomic; no other process can inter-
sperse data.
It is assumed that after the pipe has been set up, two (or more) cooperating processes (created by subsequent fork calls) will pass data
through the pipe with read and write calls.
The Shell has a syntax to set up a linear array of processes connected by pipes.
Read calls on an empty pipe (no buffered data) with only one end (all write file descriptors closed) returns an end-of-file.
SEE ALSO
sh(1), read(2), write(2), fork(2)
DIAGNOSTICS
The function value zero is returned if the pipe was created; -1 if too many files are already open. A signal is generated if a write on a
pipe with only one end is attempted.
BUGS
Should more than 4096 bytes be necessary in any pipe among a loop of processes, deadlock will occur.
ASSEMBLER
(pipe = 42.)
sys pipe
(read file descriptor in r0)
(write file descriptor in r1)
PIPE(2)