从 go 更改 *C.char 的正确方法

Question

我是 go 和 cgo 的新手，在浏览互联网一段时间后，我还没有想出一种从 go 中更改 char* 的好而快速的方法。

从 go& 更改 *C.char 的最快方法是什么

这是我的代码和我尝试更改字符串的尝试（它不起作用）

package asciiEngine

// #include <windows.h>

import "C"

type Screen struct {

    Width, Height int

    Length        C.ulong

    Data          *C.char

    GoData        string

    HConsole      C.HANDLE

    BytesWritten  C.DWORD

    Start         C.COORD

}

func (s Screen) Draw() {

    C.WriteConsoleOutputCharacter(s.HConsole, s.Data, s.Length, s.Start, &s.BytesWritten)

}

func CreateScreen(width, height int) Screen {

    screen := Screen{

        Width:        width,

        Height:       height,

        Length:       C.ulong(width * height),

        Data:         (*C.char)(C.malloc(C.ulonglong(width * height))),

        HConsole:     C.CreateConsoleScreenBuffer(C.GENERIC_READ|C.GENERIC_WRITE, 0, nil, C.CONSOLE_TEXTMODE_BUFFER, nil),

        BytesWritten: 0,

    }

    screen.GoData = C.GoString(screen.Data) // my attempt to get a reference to the C string

    //C.SetConsoleActiveScreenBuffer(screen.HConsole)

    return screen

}

主要去：

package main

// #include "stdio.h"

// void print(char* data) {

//  printf(data);

// }

import "C"

import (

    "fmt"

    "github.com/demantar/ascii-engine"

)

func main() {

    screen := asciiEngine.CreateScreen(100, 50)

    C.print((*C.char)(screen.Data))

    fmt.Println()

    screen.GoData = "askdssdfselkkskdkflsekfjdkjfksjeflsdkfjjekdjflskasdfkksdjjekdskdfjkskd"

    C.print((*C.char)(screen.Data))

}

输出

P

P

我对 C 也很陌生，我正在这样做，因为我找不到一个库来做这件事

Answer 1

例如，用作底层C数组的gDataGo切片引用。bytecDatacharpackage mainimport (    "fmt"    "unsafe")/*#include <stdlib.h>#include <stdio.h>#include <string.h>int printData(unsigned char *data) {    return printf("cData: %lu \"%s\"\n", (long unsigned int)strlen(data), data);}*/import "C"func main() {    // Allocate C data buffer.    width, height := 8, 2    lenData := width * height    // add string terminating null byte    cData := (*C.uchar)(C.calloc(C.size_t(lenData+1), C.sizeof_uchar))    // When no longer in use, free C allocations.    defer C.free(unsafe.Pointer(cData))    // Go slice reference to C data buffer,    // minus string terminating null byte    gData := (*[1 << 30]byte)(unsafe.Pointer(cData))[:lenData:lenData]    // Write and read cData via gData.    for i := range gData {        gData[i] = '.'    }    copy(gData[0:], "Data")    gData[len(gData)-1] = 'X'    fmt.Printf("gData: %d %q\n", len(gData), gData)    C.printData(cData)}输出：gData: 16 "Data...........X"cData: 16 "Data...........X"