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What Is Dangling Pointer And How To Avoid It? |
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Answer» After a call to free(p) MAKES a subsequent REFERENCE to *p ILLEGAL, i.e. THOUGH the storage to p is freed but the value of p(address) remain unchanged .so the object at that address may be used as the value of *p (i.e. there is no way to detect the illegality).Here p is called dangling pointer. To avoid this it is better to set p to NULL after executing free(p).The null pointer value doesn’t reference a storage location it is a pointer that doesn’t point to anything. After a call to free(p) makes a subsequent reference to *p illegal, i.e. though the storage to p is freed but the value of p(address) remain unchanged .so the object at that address may be used as the value of *p (i.e. there is no way to detect the illegality).Here p is called dangling pointer. To avoid this it is better to set p to NULL after executing free(p).The null pointer value doesn’t reference a storage location it is a pointer that doesn’t point to anything. |
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