GO调用C语言之字符串传递

C： hello.h

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

char *abc();
int strnum(char *str);

C:  hello.c

char *abc()
{
    char a[]="teststring"
    int byte_len=(int)sizeof(a);
    char *b=(char*)malloc(byte_len*sizeof(char));
    sprintf(b,"%s",a)
    return b;
}
int strnum(char *str){
    int len=strlen(str);
    return len;
}

GO: main.go

package main

// #include <stdlib.h>
// #include "./hello.h"

import "C"
import (
    "fmt"
    "unsafe"
)


func main(){

    cs:=C.abc() //C返回字符串的b指针
    ss:=C.GoString(cs) //将指针转化为string
    defer C.free(unsafe.Pointer(cs)) //释放在C中申请的内存空间
    fmt.println(ss) //ss为获取到C返回的字符串

    cs2 := C.CString("sdfs")  // C.CString() to *C.char
    defer C.free(unsafe.Pointer(cs2)) //释放在C中申请的内存空间
    fmt.Println("num=", C.strnum(cs2))  //必须通过C.CString("sdfs")转换才能传递


}