Core Dump/Segmentation fault is a specific kind of error caused by accessing memory that “does not belong to you.”
•When a piece of code tries to do read and write operation in a read only location in memory or freed block of memory, it is known as core dump.
•It is an error indicating memory corruption.
Common segmentation fault scenarios:
Modifying a string literal :
The below program may crash (gives segmentation fault error) because the line *(str+1) = ‘n’ tries to write a read only memory.
int main()
{
char *str;
/* Stored in read only part of data segment */
str = "GfG";
/* Problem: trying to modify read only memory */
*(str+1) = 'n';
return 0;
}
•Accessing an address that is freed :
Here in the below code, the pointer p is dereferenced after freeing the memory block, which is not allowed by the compiler. So it produces the error segment fault or abnormal program termination at runtime.
Example:
// C++ program to illustrate// Core Dump/Segmentation fault
#include <iostream>
using namespace std;
int main(void)
{
// allocating memory to p
int* p = (int*) malloc(8*sizeof(int));
*p = 100;
// deallocated the space allocated to p
free(p);
// core dump/segmentation fault
// as now this statement is illegal
*p = 110;
return 0;
}
// This code is contributed by shivanisinghss2110
