[QUOTE]Don't use a signal handler, if at all possible./QUOTE]
do u mean that it is preferred not to use one of the following apis:
1.signal
2.sigaction
it looks strange to me why shouldn't i do this?
anyway i use sigwait as u suggested,
here is my code where:
1. i block 3 signals in the main thread.
2. i create another thread whose signals will be inherited from the main thread signals i.e. the 3 signals are blocked in the child thread aslo.
but i have a question here: How can i receive these signals in the child thread, they are already blocked?
3. i call sigwait in the child thread.
My results after executing the following code are:
1. when i pressed CTRL + C, i could successfully receive the SIGINT in the child thread & the SIGINT is printed on the stdout.
2. when i tried to send the same signal inside the ISR of an interrupt using
send_sig_info i receive nothing.can anyone tell me why?
[CODE]
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include<fcntl.h>
#include<assert.h>
static sigset_t signal_mask; /* signals to block */
void *signal_thread (void *arg);
int main (int argc, char *argv[])
{
int configfd;
char buf[10]={0};
pthread_t sig_thr_id; /* signal handler thread ID */
int rc; /* return code */
sigemptyset (&signal_mask);
sigaddset (&signal_mask, SIGINT);
sigaddset (&signal_mask, SIGTERM);
sigaddset (&signal_mask, SIGUSR1);
/* kernel needs to know our pid to be able to send us a signal ->
* we use device file for this -> do not forget to insert the module.
*/
configfd = open("/dev/DSP-B_DEVICE", O_WRONLY);
if(configfd < 0)
{
perror("open");
printf("Can't open the DSP-B_Device");
assert(0);
return;
}
sprintf(buf, "%d", getpid());
if (write(configfd, buf, strlen(buf) + 1) < 0)
{
perror("fwrite");
/*return -1;*/
printf("Can't write to the DSP-B_Device");
return;
}
rc = pthread_sigmask (SIG_BLOCK, &signal_mask, NULL);
if (rc != 0)
{
/* handle error */
}
/* any newly created threads inherit the signal mask */
rc = pthread_create (&sig_thr_id, NULL, signal_thread, NULL);
if (rc != 0) {
/* handle error */
printf("cant create thread\n");
}
pause();
}
void *signal_thread (void *arg)
{
int sig_caught; /* signal caught */
int rc; /* returned code */
rc = sigwait (&signal_mask, &sig_caught);
if (rc != 0) {
/* handle error */
}
switch (sig_caught)
{
case SIGUSR1:
printf("SIGUSR1\n");
break;
case SIGINT: /* process SIGINT */
printf("SIGINT\n");
break;
case SIGTERM: /* process SIGTERM */
break;
default: /* should normally not happen */
fprintf (stderr, "\nUnexpected signal %d\n", sig_caught);
break;
}
}/CODE]
