printf("ph: %u\n", EVIOCGRAB());

open my $dev, "<", "/dev/input/event7" or die $!;
grab($dev->fileno, 1);

__END__
__C__

#include <linux/input.h>

void grab(int fd, int act) {
   printf("c: %u\n", EVIOCGRAB);
   int r =  ioctl(fd, EVIOCGRAB, act);
   printf("grab: %d\n", r);
}