👀 Views: 53 💬 Answers: 1 📅 Created: 2025-06-11

c function-pointers structs C

I tried several approaches but none seem to work... I've been working on this all day and I'm maintaining legacy code that I'm getting frustrated with Quick question that's been bugging me - I'm working on a personal project and I tried several approaches but none seem to work... I'm working with a strange scenario with function pointers in a struct in C. Despite initializing the function pointers, I'm getting a null pointer dereference when I try to call them. 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 x) { printf("Value: %d\n", x); } int main() { MyStruct *my_struct = malloc(sizeof(MyStruct)); my_struct->func_ptr = my_function; // Uncommenting the next line leads to a crash // my_struct->func_ptr(10); free(my_struct); return 0; } ``` In this example, I allocate memory for `my_struct`, assign `my_function` to `func_ptr`, and then call `func_ptr` with an argument. However, when I uncomment the line to call the function, I get a segmentation fault. I’ve checked that my_struct is not null after allocation, and I believe the function pointer is correctly assigned. For my development environment, I am using GCC version 11.2 on Linux. I’ve also tried adding print statements after the assignment to verify that `func_ptr` was set properly, and the output is as expected. Does anyone know what could be causing this scenario? Am I missing a critical step with the function pointer or the struct initialization? I'm working on a web app that needs to handle this. What am I doing wrong? What are your experiences with this? I'm using C LTS in this project. This is happening in both development and production on macOS. This issue appeared after updating to C LTS. Could someone point me to the right documentation? I've been using C for about a year now. Any advice would be much appreciated.