golang modifies dll pointer

In Golang, modifying the pointer of the DLL file is an important task, because the pointer in the DLL file is the key to connecting multiple modules. However, due to the special nature of the Golang language, it is relatively difficult to modify the DLL pointer.

Below, we will introduce one by one how to modify the DLL pointer in Golang.

1. Understand the Golang memory model

In Golang, the memory model is based on pointers. Therefore, we need to understand the use of pointers and their characteristics. In Golang, a pointer is a value that points to a memory address and can be used to read or modify the memory value at this address. Pointers can also be used to point to the address of a function, variable, or other data type.

In Golang, the pointer is declared as follows:

var ptr *int //Declare a pointer to int type

ptr = &num //Change the address of num Assign a value to the pointer ptr

. Among them, the & operator returns a pointer to a variable, and the * operator is used to dereference the pointer, that is, to read the value at the memory address pointed by the pointer.

2. Import DLL files

To import DLL files in Golang, you need to use the syscall package. Before importing the DLL file, we need to define some function pointers. These function pointers are declared in the DLL file, and we need to access them through pointers.

For example, if we want to import a DLL file named "mylib.dll", and it contains a function named "SetPointer", we need to use the following code:

import (

 "syscall"
 "unsafe"

)

type SetPointerType func(ptr *int) int

var (

 myLib *syscall.LazyDLL
 setPointerFunc SetPointerType

)

func init() {

 myLib = syscall.NewLazyDLL("mylib.dll")
 setPointerFunc = myLib.NewProc("SetPointer").Addr()

}

In this code segment, we first define a SetPointerType type, which is a function type that receives a pointer to int type as a parameter and returns a value of int type.

After that, we use the LazyDLL function to import the mylib.dll file, and use the NewProc function to obtain the address of the SetPointer function.

3. Modify the DLL pointer

In the previous code segment, we have obtained the address of the SetPointer function, and now we can use it to modify the value of the pointer.

For example, for the following code:

num := 1 //This is an int type variable

ptr := &num //Assign the address of num to ptr Pointer

ret := setPointerFunc(ptr) //Pass the pointer to the setPointer function

fmt.Println(*ptr) //Output the value of the pointer

Among them, setPointerFunc The function points to the SetPointer function in the DLL file. We pass the pointer ptr as a parameter to this function. The function will modify the value at the corresponding address to 100 and return a value. Finally, we read the value on pointer ptr and print it.

It should be noted that in Golang, the copying of pointers is shallow copying, that is, only the value of the pointer is copied, but the value at the memory address pointed by the pointer is not copied. Therefore, you need to be careful when modifying pointers to avoid unexpected effects.

4. Summary

Modifying DLL pointers in Golang is a relatively basic task. You need to understand the Golang memory model and how to use pointers, and how to import DLL files. Modification of DLL pointers requires caution to avoid unexpected effects. Correctly modifying the DLL pointer can enhance the flexibility and scalability of the program and improve code reusability.

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