如何在C中将XML文件读入缓冲区？

sudo apt-get install libxml2-dev

#include<stdio.h>
#include <stdlib.h>
#include<string.h>
#include <libxml/parser.h>
#include <libxml/tree.h>

int main(int argc, char *argv[]) {
    if (argc != 2) {
        printf("Usage: %s <xml-file>\n", argv[0]);
        return 1;
    }

    const char *filename = argv[1];
    xmlDocPtr doc;
    xmlNodePtr root_element;

    // 解析XML文件
    doc = xmlReadFile(filename, NULL, 0);
    if (doc == NULL) {
        printf("Failed to parse the XML file.\n");
        return 1;
    }

    // 获取根元素
    root_element = xmlDocGetRootElement(doc);
    if (root_element == NULL) {
        printf("Failed to get the root element.\n");
        xmlFreeDoc(doc);
        return 1;
    }

    // 递归遍历XML文档并打印内容
    xmlNodePtr current_node = root_element;
    while (current_node != NULL) {
        if (current_node->type == XML_ELEMENT_NODE) {
            printf("Element: %s\n", current_node->name);
            xmlAttrPtr attr = current_node->properties;
            while (attr != NULL) {
                printf("Attribute: %s=%s\n", attr->name, attr->children->content);
                attr = attr->next;
            }
        } else if (current_node->type == XML_TEXT_NODE) {
            printf("Text: %s\n", current_node->content);
        }
        current_node = current_node->children;
    }

    // 释放内存
    xmlFreeDoc(doc);
    return 0;
}