I think , in g() function , when ${1} fd goes to background ,f() function process at once,after then pipe is missing for that created 63fd..
therefore `/dev/fd/63` fd can not found by the g function.so g() function can not call f() function via same fd at the same time..
maybe you can try like this
Code:
..............
g() {
exec 4<${1}
f 1 <${1} &
f 2 <&4
}
...............
.........
regards
ygemici
You wouldn't want exec there. Better would be to put the redirect after the function definition. Yours is essentially equivalent to the example before it.
Anyway my question was mostly answered on the Bash mailing list.
POSIX says that background processes are always supposed to implicitly have their stdin redirected to /dev/null. Bash for some reason only sometimes follows this, and the pipe somehow affects whether that happens. The background processes shouldn't ever be getting input unless stdin is explicitly redirected. The 5th example from an updated version of the above shows another strange behavior where stdin of a list is determined by any redirects in the list.
How do you capture the return code from a background process?
I am dumping data to a fifo and then processing it in a c program.
I need to know that the sql finished successfully to ensure no missing data. Thanks.
ex.
sqlplus user/password < get_data.sql > data_fifo.txt &
bin/process_data... (2 Replies)
hi there,
here's what i need in my korn-shell:
... begin korn-shell script
... nohup process_A.ksh ; nohup process_B.ksh &
... "other stuff"
... end lorn-shell script
in plain english i want process A and process B to run in the background so that the script can continue doing... (6 Replies)
Hey guys,
I am writing a very simple dummy shell in C++ and I am having trouble getting a process to run in the background. First of all, the shell has to recognize when I input a "&" at the end of the command, then it has to stick it in the background of the shell.
I understand that if I want... (6 Replies)
Hi!
First of all, let me warn you I'm quite new to the world of LINUX and Operating Systems understanding, so that's why I pose these newbie and stupid qustions...
Anyway, I'm trying to build my own simple shell in C and I'm getting some problems in implementing the background process ('&')... (10 Replies)
I have installed oracle 10g on suse sles9. I do not see oracle background processes.
ps -ef|grep ora_ gives me environment variables junk.
ps -ef|grep smon does not show anything however database is up and running.
Any idea how to tweak that? (1 Reply)
Hi,
Inorder to improve the performance, I am trying to execute my command as a background process..
For eg: To zip large numbers of files present in a directory instead of using a single process, i do follow the below method:
gunzip -c > / &... (3 Replies)
Hi,
I need to establish a procedure that will start an application in background each time my remote Solaris server is (re)started. This would be a kind of daemon. I am no sysadmin expert, so I am looking for pointers.
How should I proceed? What are the main steps?
Thanks,
JVerstry (9 Replies)
Ok guys so I have my first dummy shell almost done except for one tiny part: I do not know how to run a process in the background, from the code!
I already know how to do that in a normal shell:
$ program &
However, no clue when it comes to how to program that thing. :eek:
A very... (2 Replies)
Hi,
I have a schell script parent.ksh from which I am calling three background processes a.ksh,b.ksh and c.ksh. Once these three processes completes the next step in parent.ksh should execute. How to achieve this?
Please help me....
Thanks... (1 Reply)
How do I list the process in a Unix based system which are running in background?
The following are options that I'm aware of, but they may not be appropiate.
a. using ps -ef , and getting records of processes for which STATUS='S'(uninterruptible sleep)
b. using jobs -l, and filtering... (5 Replies)
Discussion started by: kumarjt
5 Replies
LEARN ABOUT DEBIAN
explain_pipe_or_die
explain_pipe_or_die(3) Library Functions Manual explain_pipe_or_die(3)NAME
explain_pipe_or_die - create pipe and report errors
SYNOPSIS
#include <libexplain/pipe.h>
void explain_pipe_or_die(int *pipefd);
DESCRIPTION
The explain_pipe_or_die function is used to call the pipe(2) system call. On failure an explanation will be printed to stderr, obtained
from explain_pipe(3), and then the process terminates by calling exit(EXIT_FAILURE).
This function is intended to be used in a fashion similar to the following example:
explain_pipe_or_die(pipefd);
pipefd The pipefd, exactly as to be passed to the pipe(2) system call.
Returns:
This function only returns on success. On failure, prints an explanation and exits.
SEE ALSO pipe(2) create pipe
explain_pipe(3)
explain pipe(2) errors
exit(2) terminate the calling process
COPYRIGHT
libexplain version 0.52
Copyright (C) 2009 Peter Miller
explain_pipe_or_die(3)
10-06-2011
