pi 4b C语言搜索wifi列表

以下是使用C语言搜索WiFi列表的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>

#define MAX_SSID_LENGTH 32

typedef struct _wifi_info
{
    char ssid[MAX_SSID_LENGTH];
    int signal_strength;
} wifi_info;

int main()
{
    int sock_fd;
    struct ifreq ifr;
    char iface[] = "wlan0";
    char ssid[MAX_SSID_LENGTH];
    wifi_info wifi_list[10];
    int wifi_count = 0;
    int i;

    // Open a socket to get WiFi information
    sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock_fd < 0)
    {
        perror("socket");
        exit(1);
    }

    // Set the interface name
    strncpy(ifr.ifr_name, iface, IFNAMSIZ);

    // Get the WiFi information
    if (ioctl(sock_fd, SIOCGIWSCAN, &ifr) < 0)
    {
        perror("ioctl");
        exit(1);
    }

    // Parse the WiFi information
    char *p = ifr.ifr_data;
    while (p < ifr.ifr_data + ifr.ifr_len)
    {
        struct iw_event *event = (struct iw_event *)p;
        if (event->cmd == SIOCGIWAP)
        {
            // Get the MAC address of the access point
            char mac[18];
            sprintf(mac, "%02x:%02x:%02x:%02x:%02x:%02x",
                event->u.ap_addr.sa_data[0], event->u.ap_addr.sa_data[1],
                event->u.ap_addr.sa_data[2], event->u.ap_addr.sa_data[3],
                event->u.ap_addr.sa_data[4], event->u.ap_addr.sa_data[5]);

            // Get the signal strength
            int signal_strength = event->u.qual.level;

            // Get the SSID
            char *ssid_data = (char *)event + IW_EV_POINT_LEN;
            int ssid_len = event->u.essid.length;
            memcpy(ssid, ssid_data, ssid_len);
            ssid[ssid_len] = '\0';

            // Add the WiFi info to the list
            if (wifi_count < 10)
            {
                strncpy(wifi_list[wifi_count].ssid, ssid, MAX_SSID_LENGTH);
                wifi_list[wifi_count].signal_strength = signal_strength;
                wifi_count++;
            }
        }
        p += event->len;
    }

    // Print the WiFi list
    for (i = 0; i < wifi_count; i++)
    {
        printf("SSID: %s, Signal Strength: %d\n", wifi_list[i].ssid, wifi_list[i].signal_strength);
    }

    // Close the socket
    close(sock_fd);

    return 0;
}

该代码打开一个套接字以获取WiFi信息，并在搜索到的SSID列表中列出前10个SSID及其信号强度。该代码使用Linux套接字编程（socket），并使用ioctl函数获取WiFi信息。要使用此代码，请确保已启用wlan0接口，并在终端运行以下命令：

sudo ifconfig wlan0 up
sudo ./search_wifi
``