Why Returning Pointers to Local C Structs Causes Segmentation Faults

In C programming, local variables declared inside a function are allocated on the stack and destroyed the moment that function returns. If a pointer to such a local struct is returned or misused across function boundaries, it becomes a dangling pointer referencing invalid memory. Accessing this pointer triggers a segmentation fault, a common pitfall for developers transitioning from memory-managed languages like JavaScript. The safe alternative is to allocate the struct in the caller function and pass its address down to any function that needs to modify it, keeping the memory lifecycle tied to the caller's scope. This pattern ensures crash-free execution and is considered standard practice in systems programming.