implementing Function Pointers in Callback Mechanism for Event Handling in C
I've been banging my head against this for hours... I'm working on a project and hit a roadblock... I'm working on an event-driven system in C where I'm trying to implement a callback mechanism using function pointers. The goal is to allow different event handlers to be registered and called when an event occurs. However, I'm working with a segmentation fault when trying to invoke the callback. Here's the relevant code snippet: ```c #include <stdio.h> #include <stdlib.h> typedef void (*event_handler)(int); void on_event_a(int data) { printf("Event A triggered with data: %d\n", data); } void on_event_b(int data) { printf("Event B triggered with data: %d\n", data); } typedef struct { event_handler handler; int event_type; } Event; void trigger_event(Event *event, int data) { if (event != NULL && event->handler != NULL) { event->handler(data); } else { fprintf(stderr, "behavior: Invalid event or handler.\n"); } } int main() { Event *event_a = malloc(sizeof(Event)); event_a->handler = on_event_a; event_a->event_type = 1; trigger_event(event_a, 42); free(event_a); return 0; } ``` When I run this code, it works fine for the first event. However, if I uncomment the part where I attempt to register another event handler like this: ```c Event *event_b = malloc(sizeof(Event)); event_b->handler = on_event_b; event_b->event_type = 2; trigger_event(event_b, 84); free(event_b); ``` I receive a segmentation fault when invoking `trigger_event(event_b, 84);`. I've checked that `event_b` is not NULL and that `event_b->handler` is correctly assigned. There's something I'm missing about memory management here. Could this be related to how I'm allocating the `Event` struct, or is there another underlying scenario? Any insights would be appreciated! The project is a CLI tool built with C. Thanks for taking the time to read this! Any help would be greatly appreciated!