How Does Go's Pass-by-Value Mechanism Work with Pointers?

Unveiling the Mystery of Passing by Reference and Value in Go Functions

In Go, the concept of passing by reference and value might seem perplexing initially. To clarify, Go employs pass-by-value in all its glory, even when dealing with pointers. When you pass a pointer to a function, you essentially pass its value, not the referenced object.

The Purpose of the Asterisk (*) in Function Arguments

When you see an asterisk (*) before a type in a function argument like func PutTasks(db *sql.DB), it signifies that the argument is of type "pointer to sql.DB," contrasting it from the type "sql.DB." This distinction is crucial because the function will operate on the referenced object through this pointer.

The Benefit of Passing Pointers

Passing pointers provides a mechanism for sharing values between the calling function and the called function. Any modifications to the referenced object within the called function will be visible to the caller. This is essentially what Java's object passing achieves by default, while Go requires explicit usage of pointers for such sharing.

For instance, suppose you have a Setter function that needs to modify an object's property. In Java, this would be straightforward, but in Go, without pointers, the function would merely receive a copy of the object and any changes made would not be reflected in the original. By passing a pointer to the Setter function, you effectively allow the function to operate on the original object, enabling changes that persist beyond the function call.

Additional Resources

To delve deeper into this subject, refer to the following resources:

• Go tour on Pointers: https://go.dev/tour/pointers
• Go spec on Pointers: https://go.dev/ref/spec#Pointers
• Go spec on Address Operators: https://go.dev/ref/spec#Address_Operators

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