Segmentation Fault

runtime

Segmentation fault (core dumped)

Description

The program tried to access memory it doesn't have permission to access.

Common Causes

• Dereferencing a NULL pointer
• Accessing an array out of bounds
• Using a dangling pointer (after free)
• Stack overflow (excessive recursion)

Example of Error

Error Code

int main() {
    int *ptr = NULL;
    *ptr = 10;  // Dereferencing NULL pointer
    return 0;
}

Solution

Check pointers before dereferencing them and ensure array accesses are within bounds.

Corrected Code

#include <stdlib.h>

int main() {
    int *ptr = malloc(sizeof(int));
    if (ptr != NULL) {
        *ptr = 10;
        free(ptr);
    }
    return 0;
}

Additional Tips

• Always check if malloc/calloc returned NULL before using the pointer
• Be careful with pointer arithmetic
• Use tools like Valgrind to detect memory errors
• Set pointers to NULL after freeing them to avoid dangling pointers