12-02-2011
Quote:
Originally Posted by
DendyGamer
Why "signal safety" may change something? Signals are blocked, when signal action called.
It means, you're not allowed to call pthread_join(*s,NULL); inside a signal handler, and the results can't be predicted when you do so. It may work and betray you in strange ways later. It may do incorrect things in a less than obvious way. It may blow up immediately. It may work in this system but fail when ported to another system or your kernel is upgraded. In short, you're not supposed to do it.
The only signal-safe IPC I know of is sem_wait.
10 More Discussions You Might Find Interesting
1. Programming
I am trying to send a SIGUSR1 to a set of process. Please tell
me how to do. I've tried the system call raise(int sig) but it just
raise a signal of to the 'current process.'
My program is about a network chat server. When a client
connects in, The main process will fork a new process... (1 Reply)
Discussion started by: Namely
1 Replies
2. UNIX for Advanced & Expert Users
hi
I have created a application which uses SIGUSR2. It send this signal to server and waits for signal SIGUSR2 from server after server performing some operation server sends SIGUSR2 back to the application. The application then quits.
This works fine which ran from terminal , but when I... (3 Replies)
Discussion started by: khan_069
3 Replies
3. Programming
I am using the signal function, and passing it a function named quit procedure...I get the following warning....
passing arg2 of signal from incompatible pointer type...
void quit_procedure(void); //this is the way i define my prototype...
signal(SIGINT, quit_procedure);
Please guide... (5 Replies)
Discussion started by: jacques83
5 Replies
4. Programming
#include<signal.h>
void suicide();
main()
{
printf("use CTRL \\ for exiting \n");
//signal(SIGINT,SIG_DFL);
signal(SIGQUIT,suicide);
for (;;);
}
void suicide()
{ printf("hello here you r in the suicide code ");
}
i was just starting with signals .. and tried this ,, but in the... (10 Replies)
Discussion started by: narendra.pant
10 Replies
5. Programming
Hi,
I have a daq program that runs in an infinite loop until it receives SIGINT. A handler catches the signal and sets a flag to stop the while loop. After the loop some things have to be cleaned up.
The problem is that I want my main while loop to wait until the next full second begins, to... (2 Replies)
Discussion started by: soeckel
2 Replies
6. Programming
i wrote handler for sigsegv such that i can allocate memory for a variable to which
sigsegv generated for illlegal acces of memory.
my code is
#include <signal.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
char *j;
void segv_handler(int dummy)
{
j=(char *)malloc(10);
... (4 Replies)
Discussion started by: pavan6754
4 Replies
7. Programming
hi friends i have a problem in signal handling ...
let me explain my problem clearly..
i have four process ..
main process forks two child process and each child process again forks another new process respectively...
the problem is whenever i kill the child process it is reforking and the... (2 Replies)
Discussion started by: senvenugopal
2 Replies
8. Programming
Hi all,
Sorry about the title,at first i decided to ask a problem about the signal mechanism,however,i'm now figured it out.Sorry to forget modify the title:wall:.I had a small problem that if i use the code which is commented,the code would get a segment fault,while the above code NOT.what's... (4 Replies)
Discussion started by: homeboy
4 Replies
9. Programming
i m unble to execute code of
signal handler using
a) Wait b) Waitpid (1 Reply)
Discussion started by: madhura
1 Replies
10. Linux
hey,
i have been facing a very fatel error with dovecot..
i am getting this error in my dovecot.log file
dovecot: Feb 13 15:21:02 Fatal: chdir(/var/mail/folders/user1) failed with uid 1001: Permission denied
dovecot: Feb 13 15:21:02 Error: child 18732 (imap) returned error 89
dovecot: Feb... (3 Replies)
Discussion started by: htshshrm2
3 Replies
LEARN ABOUT SUSE
sysv_signal
SYSV_SIGNAL(3) Linux Programmer's Manual SYSV_SIGNAL(3)
NAME
sysv_signal - signal handling with System V semantics
SYNOPSIS
#define _GNU_SOURCE
#include <signal.h>
typedef void (*sighandler_t)(int);
sighandler_t sysv_signal(int signum, sighandler_t handler);
DESCRIPTION
The sysv_signal() function takes the same arguments, and performs the same task, as signal(2).
However sysv_signal() provides the System V unreliable signal semantics, that is: a) the disposition of the signal is reset to the default
when the handler is invoked; b) delivery of further instances of the signal is not blocked while the signal handler is executing; and c) if
the handler interrupts (certain) blocking system calls, then the system call is not automatically restarted.
RETURN VALUE
The sysv_signal() function returns the previous value of the signal handler, or SIG_ERR on error.
ERRORS
As for signal(2).
CONFORMING TO
This function is nonstandard.
NOTES
Use of sysv_signal() should be avoided; use sigaction(2) instead.
On older Linux systems, sysv_signal() and signal(2) were equivalent. But on newer systems, signal(2) provides reliable signal semantics;
see signal(2) for details.
The use of sighandler_t is a GNU extension; this type is only defined if the _GNU_SOURCE feature test macro is defined.
SEE ALSO
sigaction(2), signal(2), bsd_signal(3), feature_test_macros(7), signal(7)
COLOPHON
This page is part of release 3.25 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/.
2007-05-04 SYSV_SIGNAL(3)