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1. UNIX for Advanced & Expert Users
Hi All,
The problem statement is as below:
Problem: A process (exe) is getting executed in background. The output of this process is getting logged in a file. After successfully running for some time the process gets terminated. In the log file following is present:
^M[7m Interrupt ^M[27m... (8 Replies)
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2. UNIX for Dummies Questions & Answers
I am having trouble with folowing
sigset_t s; // now s represents set of signals
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5. Programming
How can use signals in a C program If i want a child program to signal it's parent program that it(child) program has completed the task that it was assigned.:confused: (2 Replies)
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(posted this in the scripting forum as well, but figured it should go here) So, what's going on is this:
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Hi all,
How can I get the list of all Threads and the Total count of threads under a particular process ?
Do suggest !!
Awaiting for the replies !!
Thanks
Varun:b: (2 Replies)
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I want to handle signals in a process that involves lots of threads. Now I do know that there should be a dedicated thread that will actually be traping signals and then these signals will be ditributed to actual threads.
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9. Programming
Hi
In my process there are few threads. Now, lets say all the threads are blocked for some reason or other..
now i read it somewhere that the kernel in this situation sends in some signal which can be caught.
please let me know what signal is it and more details about that..
Thanks in... (1 Reply)
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10. Programming
does the way of handling, interrupting signals in HP-UX same as that of solaris. If there is difference than what it is.?:confused: (1 Reply)
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PTHREAD_SIGNAL(3) Library Functions Manual PTHREAD_SIGNAL(3)
NAME
pthread_sigmask, pthread_kill, sigwait - handling of signals in threads
SYNOPSIS
#include <pthread.h>
#include <signal.h>
int pthread_sigmask(int how, const sigset_t *newmask, sigset_t *oldmask);
int pthread_kill(pthread_t thread, int signo);
int sigwait(const sigset_t *set, int *sig);
DESCRIPTION
pthread_sigmask changes the signal mask for the calling thread as described by the how and newmask arguments. If oldmask is not NULL, the
previous signal mask is stored in the location pointed to by oldmask.
The meaning of the how and newmask arguments is the same as for sigprocmask(2). If how is SIG_SETMASK, the signal mask is set to newmask.
If how is SIG_BLOCK, the signals specified to newmask are added to the current signal mask. If how is SIG_UNBLOCK, the signals specified
to newmask are removed from the current signal mask.
Recall that signal masks are set on a per-thread basis, but signal actions and signal handlers, as set with sigaction(2), are shared
between all threads.
pthread_kill send signal number signo to the thread thread. The signal is delivered and handled as described in kill(2).
sigwait suspends the calling thread until one of the signals in set is delivered to the calling thread. It then stores the number of the
signal received in the location pointed to by sig and returns. The signals in set must be blocked and not ignored on entrance to sigwait.
If the delivered signal has a signal handler function attached, that function is not called.
CANCELLATION
sigwait is a cancellation point.
RETURN VALUE
On success, 0 is returned. On failure, a non-zero error code is returned.
ERRORS
The pthread_sigmask function returns the following error codes on error:
EINVAL how is not one of SIG_SETMASK, SIG_BLOCK, or SIG_UNBLOCK
EFAULT newmask or oldmask point to invalid addresses
The pthread_kill function returns the following error codes on error:
EINVAL signo is not a valid signal number
ESRCH the thread thread does not exist (e.g. it has already terminated)
The sigwait function never returns an error.
AUTHOR
Xavier Leroy <Xavier.Leroy@inria.fr>
SEE ALSO
sigprocmask(2), kill(2), sigaction(2), sigsuspend(2).
NOTES
For sigwait to work reliably, the signals being waited for must be blocked in all threads, not only in the calling thread, since otherwise
the POSIX semantics for signal delivery do not guarantee that it's the thread doing the sigwait that will receive the signal. The best way
to achieve this is block those signals before any threads are created, and never unblock them in the program other than by calling sigwait.
BUGS
Signal handling in LinuxThreads departs significantly from the POSIX standard. According to the standard, ``asynchronous'' (external) sig-
nals are addressed to the whole process (the collection of all threads), which then delivers them to one particular thread. The thread that
actually receives the signal is any thread that does not currently block the signal.
In LinuxThreads, each thread is actually a kernel process with its own PID, so external signals are always directed to one particular
thread. If, for instance, another thread is blocked in sigwait on that signal, it will not be restarted.
The LinuxThreads implementation of sigwait installs dummy signal handlers for the signals in set for the duration of the wait. Since signal
handlers are shared between all threads, other threads must not attach their own signal handlers to these signals, or alternatively they
should all block these signals (which is recommended anyway -- see the Notes section).
LinuxThreads PTHREAD_SIGNAL(3)