is SIGINT semi blocking possible? - c

Question

Im trying to handle SIGINT. Main purpose of SIGINT in my program cancelling current search function and printing the currently avaliable results. But whenever I try to catch a SIGINT signal it just closes my program. (I ve searched so much ,please just do not say that I have not searched enough)
I have tried :
basic signal handling(as shown as below)
sigaction functionality
non-local signal handling
sigprocmask (problem with procmask whenever I block a signal I cannot catch it but I need to catch and make printing on screen)
after all i have run out of search keyword to find a solution. Any idea ? (search keyword or part of code or logic way to do it ^^)
NOTE : This text may have grammar errors. Sorry for any mistakes.
#ifdef DEBUG
#define DPRINT(file ,message ,arg) fprintf(file ,message ,arg);
#define NDPRINT(file ,message) fprintf(file ,message);
#endif
static volatile sig_atomic_t isSignalCaught = 0;
void SIGHandler(int signo);
int main(int argc, char** argv)
{
file_t *files,*nextP;
signal(SIGINT, SIGHandler);
files = findFiles("/");
while (files != NULL) {
DPRINT(stderr, "%s\n", files->fileName.string);
nextP = files->pNext;
free(files->fileName.string);
free(files);
files = nextP;
}
return(0);
}
void SIGHandler(int signo)
{
file_t *nextP;
if (signo == SIGINT) {
isSignalCaught = 1;
}
}

Answer 1

Here's an example of how to do what I think you want to do.
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <ctype.h>
typedef void(* sig_func_t )(int);
volatile sig_atomic_t keep_looping = 1;
void sig_handler(int sig_number) {
switch (sig_number) {
case SIGINT:
keep_looping = 0;
break;
}
}
int should_continue(void) {
char line[256];
while (1) {
printf("Continue? (y/n) ");
fgets(line, sizeof line, stdin);
if (tolower(line[0]) == 'y') {
keep_looping = 1;
signal(SIGINT, sig_handler);
return 1;
}
if (tolower(line[0]) == 'n')
break;
}
return 0;
}
int main (void) {
sig_func_t sig_func;
sig_func = signal(SIGINT, sig_handler);
if (sig_func == SIG_ERR) {
perror("signal");
exit(EXIT_FAILURE);
}
unsigned n = 0;
printf("Starting...\n");
while (1) {
while (keep_looping)
n++;
printf("Current value: n=%u\n", n);
if (!should_continue())
break;
}
signal(SIGINT, sig_func);
return EXIT_SUCCESS;
}