In your third step you said "Blocking every signal in the set, i.e. adding SIGILL to the set of blocked signals".
Didn't we add SIGILL in previous step?
You added it to the s variable, is all. The system hasn't been told to use it, that's what sigprocmask is for.
Quote:
If the set is empty then we only blocking SIGILL?
No. From man sigprocmask:
...meaning. you're adding SIGILL to whatever signals are currently being blocked.
Quote:
When we have empty set of signals does that mean there isn't any signals in it?
(posted this in the scripting forum as well, but figured it should go here) So, what's going on is this:
For our program, we had to create our own shell, and if the user pressed ctrl-c just at the cmdline, then this signal would be ignored, but if there is a foreground process running, let's... (0 Replies)
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)
can any one give me an example of a concurrency program in threads and signals, i.e how to deliver messages between threads using signals. thanks (0 Replies)
can any one give me an example of a concurrency program in threads and signals, i.e how to deliver messages between threads using signals. thanks (2 Replies)
Hi,
In our program, we are using SIGTERM and i tired to put break point in this function. But my debuger is unable to brake at that point.
I am working on Mac X and using XCode.
Thanks (0 Replies)
I have following problem with this code..
First time trough the main loop.....
perror gives ....blocked signal:success(all other times gives illlegal seek)
Should every time trought the main loop be success??
And the perror otside of main loop...didn't change mask:success
That line of code... (2 Replies)
I know how to add signal to a set. But what if I want to add 2 or 3 signals to the set.
I know I can use sigaddset (&set,SIGBUS)....but what if I want to add SIGBUS and SIGALRM at once. Do i have to do it like this..
sigaddset (&set,SIGBUS);
sigaddset (&set,SIGALRM);
Is there another way to... (0 Replies)
how can do this programs in c++
Program description:
Infinite loop in a program starts working with 2 seconds the screen (console) "I 'm trying" to write, but it automatically after 10 seconds, the screen "Close" will terminate the execution of typing.
c++ code (3 Replies)
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)
Discussion started by: Praty.27
8 Replies
LEARN ABOUT LINUX
rt_sigprocmask
SIGPROCMASK(2) Linux Programmer's Manual SIGPROCMASK(2)NAME
sigprocmask - examine and change blocked signals
SYNOPSIS
#include <signal.h>
int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigprocmask(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE
DESCRIPTION
sigprocmask() is used to fetch and/or change the signal mask of the calling thread. The signal mask is the set of signals whose delivery
is currently blocked for the caller (see also signal(7) for more details).
The behavior of the call is dependent on the value of how, as follows.
SIG_BLOCK
The set of blocked signals is the union of the current set and the set argument.
SIG_UNBLOCK
The signals in set are removed from the current set of blocked signals. It is permissible to attempt to unblock a signal which is
not blocked.
SIG_SETMASK
The set of blocked signals is set to the argument set.
If oldset is non-NULL, the previous value of the signal mask is stored in oldset.
If set is NULL, then the signal mask is unchanged (i.e., how is ignored), but the current value of the signal mask is nevertheless returned
in oldset (if it is not NULL).
The use of sigprocmask() is unspecified in a multithreaded process; see pthread_sigmask(3).
RETURN VALUE
sigprocmask() returns 0 on success and -1 on error.
ERRORS
EINVAL The value specified in how was invalid.
CONFORMING TO
POSIX.1-2001.
NOTES
It is not possible to block SIGKILL or SIGSTOP. Attempts to do so are silently ignored.
Each of the threads in a process has its own signal mask.
A child created via fork(2) inherits a copy of its parent's signal mask; the signal mask is preserved across execve(2).
If SIGBUS, SIGFPE, SIGILL, or SIGSEGV are generated while they are blocked, the result is undefined, unless the signal was generated by
kill(2), sigqueue(2), or raise(3).
See sigsetops(3) for details on manipulating signal sets.
SEE ALSO kill(2), pause(2), sigaction(2), signal(2), sigpending(2), sigqueue(2), sigsuspend(2), pthread_sigmask(3), sigsetops(3), signal(7)COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-10-17 SIGPROCMASK(2)