reborg is right. Using system will not help if you are going to do it that way.
Understand that system() actually forks and execs whatever command you have given. So your export command would be executed in a child process of the current running process and the environment variables would be set in the child process. When the system() call completes, the child process would end and its environment will not be visible to any further child processes that the main parent process may have. If you want to execute the script through a C program, you have to run it as:
Hi guys,
Is it possible to make SOAP calls from within Unix shell scripts?
I need to access a web service from within UNIX in order to lookup something while I am doing some parsing on a file.
Regards,
Laud (2 Replies)
Hi Everyone!
How can we make a socket() system call from a linux module executing in kernel space?
If any one knows, kindly tell me. It will be great.
I want to use the socket interface in linux kernel space for sending raw packets over the network.
Hamayun (0 Replies)
Hi,
Ho do I differentiate system call from library call?
for example if I am using chmod , how do I find out if it is a system call or library call?
Thanks
Muru (2 Replies)
Hi
I'm studing the system call. I've written a small program that return the time spent in doing some operations. Now I'd like to write one that return the time spent in user mode of a process.
I'm reading that i should use the tms struct:
clock_t times(struct tms *buf);
struct tms {... (2 Replies)
Hello,
I was asked by my boss to make a backup of one of our systems that is slated to be decommissioned. When I suggested if could tar the "/" directory he nodded and said that would do the trick,
When I try and execute the command I get EOF error. I think it is because there is not enough... (2 Replies)
Trying to figure out a load issue with a webserver. I have traced a php script and noticed the following
connect(4, {sa_family=AF_INET, sin_port=htons(3306), sin_addr=inet_addr("XX.XX.XX.XX")}, 16) = -1 EINPROGRESS (Operation now in progress) <0.000035>
poll(, 1, 2000) = 1 () <0.000120>... (5 Replies)
Hello to all,
I have Fujitsu Celzius M470 workstation which has Sun solaris system installed and want to make a complete backup of the hard drive. The existing HDD is SATA II, 500 GB.
I don't have much experience working with SUN solaris systems (not at all) but have some experience with... (5 Replies)
Discussion started by: Mick
5 Replies
LEARN ABOUT MOJAVE
tcl_detachpids
Tcl_DetachPids(3) Tcl Library Procedures Tcl_DetachPids(3)__________________________________________________________________________________________________________________________________________________NAME
Tcl_DetachPids, Tcl_ReapDetachedProcs, Tcl_WaitPid - manage child processes in background
SYNOPSIS
#include <tcl.h>
Tcl_DetachPids(numPids, pidPtr)
Tcl_ReapDetachedProcs()
Tcl_Pid
Tcl_WaitPid(pid, statusPtr, options)
ARGUMENTS
int numPids (in) Number of process ids contained in the array pointed to by pidPtr.
int *pidPtr (in) Address of array containing numPids process ids.
Tcl_Pid pid (in) The id of the process (pipe) to wait for.
int *statusPtr (out) The result of waiting on a process (pipe). Either 0 or ECHILD.
int options (in) The options controlling the wait. WNOHANG specifies not to wait when checking the process.
_________________________________________________________________DESCRIPTION
Tcl_DetachPids and Tcl_ReapDetachedProcs provide a mechanism for managing subprocesses that are running in background. These procedures
are needed because the parent of a process must eventually invoke the waitpid kernel call (or one of a few other similar kernel calls) to
wait for the child to exit. Until the parent waits for the child, the child's state cannot be completely reclaimed by the system. If a
parent continually creates children and doesn't wait on them, the system's process table will eventually overflow, even if all the children
have exited.
Tcl_DetachPids may be called to ask Tcl to take responsibility for one or more processes whose process ids are contained in the pidPtr
array passed as argument. The caller presumably has started these processes running in background and does not want to have to deal with
them again.
Tcl_ReapDetachedProcs invokes the waitpid kernel call on each of the background processes so that its state can be cleaned up if it has
exited. If the process has not exited yet, Tcl_ReapDetachedProcs does not wait for it to exit; it will check again the next time it is
invoked. Tcl automatically calls Tcl_ReapDetachedProcs each time the exec command is executed, so in most cases it is not necessary for
any code outside of Tcl to invoke Tcl_ReapDetachedProcs. However, if you call Tcl_DetachPids in situations where the exec command may
never get executed, you may wish to call Tcl_ReapDetachedProcs from time to time so that background processes can be cleaned up.
Tcl_WaitPid is a thin wrapper around the facilities provided by the operating system to wait on the end of a spawned process and to check a
whether spawned process is still running. It is used by Tcl_ReapDetachedProcs and the channel system to portably access the operating sys-
tem.
KEYWORDS
background, child, detach, process, wait
TclTcl_DetachPids(3)