In this article, if memory allocation using new is failed in C++ then how it should be handled? When an object of a class is created dynamically using new operator, the object occupies memory in the heap. Below are the major thing that must be keep in mind:
- What if sufficient memory is not available in the heap memory, and how it should be handled?
- If memory is not allocated then how to avoid the project crash?
Below is the program that occupies a large amount of memory so that the problem will occur. Use memory allocation statements in the try and catch block and for preventing memory crash and throw the exception when memory allocation is failed.
Memory Allocation is failed: std::bad_alloc
The above memory failure issue can be resolved without using the try-catch block. It can be fixed by using nothrow version of the new operator:
- The nothrow constant value is used as an argument for operator new and operator new to indicate that these functions shall not throw an exception on failure but return a null pointer instead.
- By default, when the new operator is used to attempt to allocate memory and the handling function is unable to do so, a bad_alloc exception is thrown.
- But when nothrow is used as an argument for new, and it returns a null pointer instead.
- This constant (nothrow) is just a value of type nothrow_t, with the only purpose of triggering an overloaded version of the function operator new (or operator new) that takes an argument of this type.
Below is the implementation of memory allocation using nothrow operator:
Memory allocation fails