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1. Shell Programming and Scripting
Hi all,
I am starting mgen5 for sometime depends on input from a file, in a child process. now I want to make parent to wait in this child process till mgen5 finishes, or timeout happens.
could anyone please tell me how to make parent to wait in child process in shell script?
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2. Shell Programming and Scripting
I have two scripts lets say A.expect and B.sh needs to be executed.
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3. Shell Programming and Scripting
Hi everyone
i am very new to linux , working on bash shell.
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4. Emergency UNIX and Linux Support
Hello, everyone.
Here's a program:
pid_t pid = fork();
if (0 == pid) // child process
{
execvp ...;
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I send a signal (such as SIGINT) to the parent process, the child process receive the signal as well as the parent process.
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5. Homework & Coursework Questions
1. The problem statement, all variables and given/known data:
I need to make an program that in a loop creates one parent and five children with fork(). The problem i'm trying to solve is how to delete the parent and child of the childīs process.
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6. Programming
Hi, i want that the parent process start before the child, this code doesn't work,
if the child start before the parent it wait for signal, then the father send the signal SIGALRM and the child catch it and call printf;
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Hi All,
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8. Shell Programming and Scripting
Hi All,
I have two ksh script. 1st script calls the 2nd script and the second script calls an 'C' program.
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9. Programming
Hi All,
I will be glad if you could help me resolve this problem.
I have created two detachable threads and wanted to them execute independent of the parent thread ( the main task which creates the detachable threads). But I see no output coming from the execution of two detachable threads.... (4 Replies)
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10. UNIX for Advanced & Expert Users
Hi
I have a shell script A which calls another 10 shell scripts which run in background. How do i make the parent script wait for the child scripts complete, or in other words, i must be able to do a grep of parent script to find out if the child scripts are still running.
My Code:
... (1 Reply)
Discussion started by: albertashish
1 Replies
wait(3C) Standard C Library Functions wait(3C)
NAME
wait - wait for child process to stop or terminate
SYNOPSIS
#include <sys/types.h>
#include <sys/wait.h>
pid_t wait(int *stat_loc);
DESCRIPTION
The wait() function will suspend execution of the calling thread until status information for one of its terminated child processes is
available, or until delivery of a signal whose action is either to execute a signal-catching function or to terminate the process. If more
than one thread is suspended in wait(), waitpid(3C), or waitid(2) awaiting termination of the same process, exactly one thread will return
the process status at the time of the target process termination. If status information is available prior to the call to wait(), return
will be immediate.
If wait() returns because the status of a child process is available, it returns the process ID of the child process. If the calling
process specified a non-zero value for stat_loc, the status of the child process is stored in the location pointed to by stat_loc. That
status can be evaluated with the macros described on the wait.h(3HEAD) manual page.
In the following, status is the object pointed to by stat_loc:
o If the child process terminated due to an _exit() call, the low order 8 bits of status will be 0 and the high order 8 bits will con-
tain the low order 7 bits of the argument that the child process passed to _exit(); see exit(2).
o If the child process terminated due to a signal, the high order 8 bits of status will be 0 and the low order 7bits will contain the
number of the signal that caused the termination. In addition, if WCOREFLG is set, a "core image" will have been produced; see sig-
nal.h(3HEAD) and wait.h(3HEAD).
One instance of a SIGCHLD signal is queued for each child process whose status has changed. If wait() returns because the status of a child
process is available, any pending SIGCHLD signal associated with the process ID of that child process is discarded. Any other pending
SIGCHLD signals remain pending.
If the calling process has SA_NOCLDWAIT set or has SIGCHLD set to SIG_IGN, and the process has no unwaited children that were transformed
into zombie processes, it will block until all of its children terminate, and wait() will fail and set errno to ECHILD.
If a parent process terminates without waiting for its child processes to terminate, the parent process ID of each child process is set to
1, with the initialization process inheriting the child processes; see intro(2).
RETURN VALUES
When wait() returns due to a terminated child process, the process ID of the child is returned to the calling process. Otherwise, -1 is
returned and errno is set to indicate the error.
ERRORS
The wait() function will fail if:
ECHILD The calling process has no existing unwaited-for child processes.
EINTR The function was interrupted by a signal.
USAGE
Since wait() blocks on a stopped child, a calling process wanting to see the return results of such a call should use waitpid(3C) or
waitid(2) instead of wait(). The wait() function is implemented as a call to waitpid(-1, stat_loc, 0).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Async-Signal-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
intro(2), exec(2), exit(2), fork(2), pause(2), waitid(2), ptrace(3C), signal(3C), signal.h(3HEAD), waitpid(3C), wait.h(3HEAD),
attributes(5)
SunOS 5.10 9 Jun 2004 wait(3C)