Call By Sharing

Call by sharing is a parameter-passing mechanism in programming languages where the formal parameter in a function receives a copy of the reference to the actual argument, rather than a copy of the argument's value or the argument itself. This means that while the function cannot reassign the original reference to point to a different object, it can modify the properties or elements of the object that the reference points to. It is commonly used in languages like Python, JavaScript, and Java for object types.

Also known as: Call-by-sharing, Pass by sharing, Object sharing, Reference copy, CBSharing

Why learn Call By Sharing?

Developers should understand call by sharing to avoid common bugs related to mutable objects, such as unintentionally modifying data structures passed to functions, which can lead to side effects and hard-to-debug issues. It is crucial when working with languages that use this mechanism for objects, as it affects how functions interact with arguments like lists, dictionaries, or custom objects, influencing design patterns and memory management.

Learning Resources

• docs: Python Documentation: How arguments are passed
• docs: MDN Web Docs: JavaScript function parameters
• tutorial: GeeksforGeeks: Parameter Passing Techniques
• video: YouTube: Call by Sharing Explained
• tutorial: Stack Overflow: Is Java pass-by-reference or pass-by-value?