Handle many Gpio Interruptions C++ Linux - c++

Question

I have an interruptions problem. I am working in an application which has to handle many buttons by interruptions. I am using this program to handle one:
int main(){
gpio_export(gpio);
gpio_set_dir(gpio, 0);
gpio_set_edge(gpio, "falling");
gpio_fd = gpio_fd_open(gpio);
timeout = POLL_TIMEOUT;
while (1) {
memset((void*)fdset, 0, sizeof(fdset));
fdset[0].fd = STDIN_FILENO;
fdset[0].events = POLLIN;
fdset[1].fd = gpio_fd;
fdset[1].events = POLLPRI;
rc = poll(fdset, nfds, timeout);
if (rc < 0) {
printf("\npoll() failed!\n");
return -1;
}
if (rc == 0) {
printf(".");
}
if (fdset[1].revents & POLLPRI) {
len = read(fdset[1].fd, buf, MAX_BUF);
printf("\npoll() GPIO %d interrupt occurred\n", gpio);
}
if (fdset[0].revents & POLLIN) {
(void)read(fdset[0].fd, buf, 1);
printf("POLLIN");
//printf("\npoll() stdin read 0x%2.2X\n", (unsigned int) buf[0]);
}
fflush(stdout);
}
gpio_fd_close(gpio_fd);
gpio_fd_close(gpio_fd2);
return 0;
}
It is working perfectly, my problem is that what I want to do is handle more interruptions so what I tried is this:
while (1) {
memset((void*)fdset, 0, sizeof(fdset));
fdset[0].fd = STDIN_FILENO;
fdset[0].events = POLLIN;
fdset[1].fd = gpio_fd;
fdset[1].events = POLLPRI;
rc = poll(fdset, nfds, timeout);
memset((void*)fdset2, 0, sizeof(fdset2));
fdset2[0].fd = STDIN_FILENO;
fdset2[0].events = POLLIN;
fdset2[1].fd = gpio_fd2;
fdset2[1].events = POLLPRI;
rc2 = poll(fdset2, nfds, timeout);
if (rc < 0 || rc2 < 0) {
printf("\npoll() failed!\n");
return -1;
}
if (rc == 0 || rc2==0) {
printf(".");
}
if (fdset[1].revents & POLLPRI) {
len = read(fdset[1].fd, buf, MAX_BUF);
printf("\npoll() GPIO %d interrupt occurred\n", gpio);
}
if (fdset2[1].revents & POLLPRI) {
len = read(fdset2[1].fd, buf, MAX_BUF);
printf("\npoll() GPIO %d interrupt occurred\n", gpio2);
}
if (fdset[0].revents & POLLIN) {
(void)read(fdset[0].fd, buf, 1);
printf("POLLIN");
//printf("\npoll() stdin read 0x%2.2X\n", (unsigned int) buf[0]);
}
if (fdset2[0].revents & POLLIN) {
(void)read(fdset2[0].fd, buf, 1);
printf("POLLIN");
//printf("\npoll() stdin read 0x%2.2X\n", (unsigned int) buf[0]);
}
fflush(stdout);
}
gpio_fd_close(gpio_fd);
gpio_fd_close(gpio_fd2);
return 0;
}
Basically I tried to handle two interruptions in the same program, but when I push any button nothing happend. What can I do that? shall I use threads?
Thank you guys

Answer 1

You have to merge fdset-s before you call poll. Basically the program waits at first poll call instead of waiting on first and second in parralel. So you can use threads or call one poll for all fdset-s and once.