如何將 golang 字符串添加到我在 cgo 中制作的 c 結構中。代碼如下：package main/*#include <stdio.h>#include <stdlib.h>#include <errno.h>typedef struct Point { int x, y;} Point;typedef struct Resp { char response;} Resp;*/import "C"import ( "fmt" "io/ioutil" "unsafe")type CPoint struct { Point C.Point Resp C.Resp}func main() { var r string = "Hello World" resp := unsafe.Pointer(C.char(r)) point := CPoint{ Point: C.Point{x: 1, y: 2}, Resp: C.Resp{response: resp}, } fmt.Println(point)}但是每當我運行這個，我得到這個錯誤如何解決這個問題？如何通過 r 鍵入 _Ctype_char？cannot convert r (type string) to type _Ctype_char另外，如何在 c 結構“Resp”中獲取值？package main/*#include <stdio.h>#include <stdlib.h>#include <errno.h>typedef struct Point { int x, y;} Point;typedef struct Resp { char response; // <-- How can I get this value in my go code?} Resp;*/
1 回答
森欄
TA貢獻1810條經驗 獲得超5個贊
您的代碼需要 2 個修復：
C 僅表示單個字符/字節 - 不表示字符串。C 字符串為 。
charchar*您應該使用 從 Go 分配 C 字符串，并釋放它。參見：https://pkg.go.dev/cmd/cgo#hdr-Go_references_to_C。
C.CStringC.free
以下是您使用這些修復程序的示例：
package main
// FIX: "char response" replaced with "char *response" below.
/*
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
typedef struct Point {
int x, y;
} Point;
typedef struct Resp {
char *response;
} Resp;
void fill(const char *name, Resp *r) {
printf("name: %s\n", name);
printf("Original value: %s\n", r->response);
r->response = "testing";
}
*/
import "C"
import (
"fmt"
"unsafe"
)
// NOTE: You cannot pass this struct to C.
// Types passed to C must be defined in C (eg, like "Point" above).
type CPoint struct {
Point C.Point
Resp C.Resp
}
func main() {
// FIX: Use CString to allocate a *C.char string.
resp := C.CString("Hello World")
point := CPoint{
Point: C.Point{x: 1, y: 2},
Resp: C.Resp{response: resp},
}
fmt.Println(point)
// Example of calling a C function and converting a C *char string to a Go string:
cname := C.CString("foo")
defer C.free(unsafe.Pointer(cname))
r := &C.Resp{
response: resp, // Use allocated C string.
}
C.fill(cname, r)
goResp := C.GoString(r.response)
fmt.Println(goResp)
// FIX: Release manually allocated string with free(3) when no longer needed.
C.free(unsafe.Pointer(resp))
}
- 1 回答
- 0 關注
- 94 瀏覽
添加回答
舉報
0/150
提交
取消