uintptr is an integer type in Go large enough to hold the bit pattern of any pointer. It is used for low-level memory operations and converting unsafe.Pointer for arithmetic, but it is not type-safe.
Key takeaways:
Golang is a statically typed language, meaning variable types are defined explicitly or inferred by the compiler.
uintptr is an integer type capable of storing the bit pattern of any pointer.
It is used in unsafe operations, converting unsafe.Pointer to perform arithmetic, and back to unsafe.Pointer.
Variables of uintptr type can store and print memory address values but doesn’t reference objects.
Pointers ensure type safety and prevent garbage collection, while uintptr allowing low-level memory manipulation and are not type-safe.
Use uintptr in advanced, performance-critical, or unsafe operations.
Variables contain data, which can be of different data types, or types for short. Golang is a statically typed language, which means the compiler must know the types of all the variables, either because they were explicitly indicated or because the compiler can infer the type from the code context. A type defines the set of values and the set of operations that can take place on those values.
Type uintptr in Golang is an integer type that is large enough to contain the bit pattern of any pointer. In other words, uintptr is an integer representation of a memory address. Below is how you declare a variable of type uintptr:
var var_name uintptr
uintptr is generally used to perform indirect arithmetic operations on unsafe pointers for unsafe memory access. First, unsafe.Pointer is converted to uintptr, and then the arithmetic operation is performed on uintptr. Finally, it is converted back to unsafe.Pointer, which now points to the new memory address as a result of the operation.
uintptr is also used to store and print the pointer address value. Since the variable with the type uintptr does not reference anything as it’s a plain integer, the pointer corresponding to that object can be garbage-collected.
Below is an example of how to declare and use a uintptr variable:
var var1 uintptr = uintptr(0xc82000c290)fmt.Println(var1)
In this case, var1 holds a memory address represented as an integer. When printed, the output is the integer value of the address.
package mainimport "fmt"func main() {var var1 uintptr = 0xc82000c290fmt.Println("Value of var1:", var1)fmt.Printf("Type of var1: %T", var1)}
The above code declares the variable var1 with type uintptr, which is assigned the memory address 0xc82000c290. If you run the code, you can observe that the value of var1 is displayed as an integer.
uintptrThe below comparison helps to determine when to use pointers or uintptr depending on the requirements of your program.
Feature | Pointer |
|
Purpose | References memory addresses directly. | Represents memory addresses as integers. |
Type safety | Type-safe; enforces type constraints. | Not type-safe; treated as an integer. |
Memory protection | Prevents referenced memory from being garbage collected. | Does not prevent memory from being garbage collected. |
Operations | Used for dereferencing and referencing memory. | Used for arithmetic and manipulation on addresses. |
Use case | Preferred for safe memory operations. | Used in unsafe or low-level memory operations. |
Garbage collection | Protects the object from garbage collection. | Allows garbage collection as it does not track references. |
Use pointers: When working with memory-safe, type-referenced operations.
Use uintptr: For low-level operations requiring memory manipulation or when interacting with unsafe APIs.
If you want to get more info about pointers in Go, please look into our Answer: What are pointers in Golang?
The uintptr type in Golang bridges safe and unsafe memory operations. Its primary use lies in advanced scenarios like interfacing with hardware or optimizing low-level performance-critical code.
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