CGO的奇怪操作 持续更新

主要记录下 cgo 一些写发与实际想法不同的地方.

数组传递

cgo 中 go 往 c 传递数组时, 直接传递数组会报错, 正确的传递方式是传递 数组中第1个元素的地址.

package main

/*
#include <stdio.h>
#include <string.h>

int sum(int sizes[], int num, int p[]) {
    int sum = 0;
    if (p == NULL) {
        return 0;
    }
    for (int i = 0; i < num; i++) {
        sum += p[i];
        sizes[i] =  p[i];
        printf("%d, %d\n", i, p[i]);
    }
    return sum;
}

*/
import "C"
import (
	"fmt"
)

func main() {
	sizes := []C.int{0, 0, 0, 0, 0}
	p := []C.int{C.int(1), C.int(2), C.int(3), C.int(4), C.int(5)}
  // sum := C.sum(sizes, C.int(5), p)
  // 报错 
  //    ./cgo.go:30:15: cannot use sizes (variable of type []_Ctype_int) as type *_Ctype_int in argument to (_Cfunc_sum)
  //    ./cgo.go:30:32: cannot use p (variable of type []_Ctype_int) as type *_Ctype_int in argument to (_Cfunc_sum)
	sum := C.sum(&sizes[0], C.int(5), &p[0])
	fmt.Printf("%T\n", int(sum))
}