为什么没有调用我的回调?

我正在尝试在C++(使用 g++ 编译器(中实现 fuse hello 示例 (https://lastlog.de/misc/fuse-doc/doc/html/hello_8c.html(。我不得不稍微改变一下才能做到这一点。

#define FUSE_USE_VERSION 30
#include <cstdlib>
#include <iostream>
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
static const char *hello_str = "Hello World!n";
static int hello_getattr(const char *path, struct stat *stbuf)
{
int res = 0;
memset(stbuf, 0, sizeof(struct stat));
if (strcmp(path, "/") == 0)
{
stbuf->st_mode = S_IFDIR | 0777;
stbuf->st_nlink = 2;
}
else if (strcmp(path, "/hello") == 0)
{
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = strlen(hello_str);
}
else
res = -ENOENT;
return res;
};
static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi)
{
(void) offset;
(void) fi;
if (strcmp(path, "/") != 0)
return -ENOENT;
filler(buf, ".", NULL, 0);
filler(buf, "..", NULL, 0);
filler(buf, "hello", NULL, 0);
return 0;
};
static int hello_open(const char *path, struct fuse_file_info *fi)
{
if (strcmp(path, "/hello") != 0)
return -ENOENT;
if ((fi->flags & 3) != O_RDONLY)
return -EACCES;
return 0;
};
static int hello_read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi)
{
size_t len;
(void) fi;
if(strcmp(path, "/hello") != 0)
return -ENOENT;
len = strlen(hello_str);
if (offset < len) {
if (offset + size > len)
size = len - offset;
memcpy(buf, hello_str + offset, size);
} else
size = 0;
return size;
};
static int hello_opendir(const char *path, struct fuse_file_info *fi)
{
return 0;
};
struct hello_fuse_operations : fuse_operations
{
hello_fuse_operations()
{
this->getattr = hello_getattr;
this->open = hello_open;
this->read = hello_read;
this->opendir = hello_opendir;
this->readdir = hello_readdir;
}
};
static struct hello_fuse_operations hello_oper;
int main(int argc, char** argv)
{
return fuse_main_real(argc, argv, &hello_oper, sizeof(&hello_oper), NULL);
}

我的问题是，fuse 说read和readdir没有实现，也没有调用它们，即使它们显然已经实现。

unique: 13, opcode: READDIR (28), nodeid: 1, insize: 80, pid: 16153
unique: 13, error: -38 (Function not implemented), outsize: 16

看起来我似乎在做一些基本错误的事情，但我无法弄清楚是什么。(我对C++也不是很有经验(

如何使示例正常工作？