Unexpected Behavior When Using Function Pointers with Structs in C
I've been struggling with this for a few days now and could really use some help. I'm encountering unexpected behavior when trying to use function pointers within structs. I have a struct that contains a function pointer intended to execute different behaviors based on certain conditions. However, when I assign the function pointer and call it, it leads to a segmentation fault and inconsistent outputs. Here's a simplified version of my code: ```c #include <stdio.h> #include <stdlib.h> typedef struct { void (*func_ptr)(int); } MyStruct; void my_function(int a) { printf("Function called with value: %d\n", a); } int main() { MyStruct myStruct; myStruct.func_ptr = my_function; // Simulating some condition int condition = 1; if (condition) { // Calling function pointer myStruct.func_ptr(5); } else { myStruct.func_ptr = NULL; // Intentionally setting to NULL } // This line sometimes leads to a segfault myStruct.func_ptr(10); return 0; } ``` This code works correctly when the `if` condition is true, but if I set the function pointer to `NULL` and then try to call it later, it results in a segmentation fault. I tried adding checks to make sure the function pointer is not `NULL` before calling it, but it seems that the issue is more about the pointer's state after being set to `NULL`. Is there a better design pattern I should be using to handle this situation? Any advice on best practices for managing function pointers within structs would be appreciated. I'm currently using GCC version 11.2 on Ubuntu 20.04. My development environment is Windows. Is there a better approach?