
C语言访问蓝牙的方法包括:使用系统级API、使用第三方库、直接操作蓝牙模块。本文将详细探讨使用系统级API的方法。
使用系统级API是访问蓝牙的最直接和高效的方法。例如,在Windows上,可以使用Windows API中的Bluetooth API,而在Linux上,可以使用BlueZ库。这种方法直接调用操作系统提供的功能,能够获得更高的性能和灵活性。
一、使用Windows API访问蓝牙
1、初始化蓝牙设备
在Windows环境下,首先需要使用BluetoothFindFirstDevice和BluetoothFindNextDevice函数来查找和初始化蓝牙设备。
#include <windows.h>
#include <bluetoothapis.h>
#pragma comment(lib, "Bthprops.lib")
int main() {
BLUETOOTH_DEVICE_SEARCH_PARAMS searchParams = { sizeof(BLUETOOTH_DEVICE_SEARCH_PARAMS) };
searchParams.fReturnAuthenticated = TRUE;
searchParams.fReturnRemembered = TRUE;
searchParams.fReturnUnknown = TRUE;
searchParams.fReturnConnected = TRUE;
searchParams.fIssueInquiry = TRUE;
searchParams.cTimeoutMultiplier = 1;
BLUETOOTH_DEVICE_INFO deviceInfo = { sizeof(BLUETOOTH_DEVICE_INFO) };
HBLUETOOTH_DEVICE_FIND deviceFind = BluetoothFindFirstDevice(&searchParams, &deviceInfo);
if (deviceFind == NULL) {
printf("No Bluetooth devices found.n");
return 1;
}
do {
printf("Device found: %sn", deviceInfo.szName);
} while (BluetoothFindNextDevice(deviceFind, &deviceInfo));
BluetoothFindDeviceClose(deviceFind);
return 0;
}
2、连接蓝牙设备
找到设备后,需要使用BluetoothAuthenticateDevice和BluetoothSetServiceState函数来连接到蓝牙设备。
BLUETOOTH_DEVICE_INFO deviceInfo = { sizeof(BLUETOOTH_DEVICE_INFO) };
// Fill deviceInfo with the target device's information
DWORD result = BluetoothAuthenticateDevice(NULL, NULL, &deviceInfo, NULL, 0);
if (result != ERROR_SUCCESS) {
printf("Failed to authenticate device.n");
return 1;
}
result = BluetoothSetServiceState(NULL, &deviceInfo, &HumanInterfaceDeviceServiceClass_UUID, BLUETOOTH_SERVICE_ENABLE);
if (result != ERROR_SUCCESS) {
printf("Failed to set service state.n");
return 1;
}
二、使用BlueZ库在Linux上访问蓝牙
BlueZ是Linux官方的蓝牙协议栈,提供了丰富的API供开发者使用。
1、初始化蓝牙设备
在Linux系统下,可以使用hci_open_dev和hci_inquiry函数来查找和初始化蓝牙设备。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/hci_lib.h>
int main() {
int device_id = hci_get_route(NULL);
int device_handle = hci_open_dev(device_id);
if (device_handle < 0) {
perror("Opening Bluetooth device failed");
exit(1);
}
inquiry_info *info = NULL;
int num_rsp = hci_inquiry(device_id, 8, 255, NULL, &info, IREQ_CACHE_FLUSH);
if (num_rsp < 0) {
perror("HCI inquiry failed");
close(device_handle);
exit(1);
}
for (int i = 0; i < num_rsp; i++) {
char addr[19] = { 0 };
char name[248] = { 0 };
ba2str(&info[i].bdaddr, addr);
if (hci_read_remote_name(device_handle, &info[i].bdaddr, sizeof(name), name, 0) < 0) {
strcpy(name, "[unknown]");
}
printf("Found device %s - %sn", addr, name);
}
free(info);
close(device_handle);
return 0;
}
2、连接蓝牙设备
接下来,需要使用l2cap_connect函数来连接到蓝牙设备的服务。
#include <bluetooth/l2cap.h>
struct sockaddr_l2 addr = { 0 };
addr.l2_family = AF_BLUETOOTH;
addr.l2_psm = htobs(0x1001);
str2ba(target_address, &addr.l2_bdaddr);
int sock = socket(AF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("Failed to connect to device");
close(sock);
exit(1);
}
三、使用第三方库
1、BlueCove
BlueCove是一个开源的蓝牙库,支持多个平台,包括Windows、Linux和Mac。
import javax.bluetooth.*;
import javax.microedition.io.Connector;
import javax.microedition.io.StreamConnection;
public class BluetoothClient {
public static void main(String[] args) {
try {
LocalDevice localDevice = LocalDevice.getLocalDevice();
DiscoveryAgent agent = localDevice.getDiscoveryAgent();
agent.startInquiry(DiscoveryAgent.GIAC, new DiscoveryListener() {
public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {
try {
String name = btDevice.getFriendlyName(false);
System.out.println("Discovered: " + name);
} catch (IOException e) {
e.printStackTrace();
}
}
public void inquiryCompleted(int discType) {
System.out.println("Inquiry completed.");
}
public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {}
public void serviceSearchCompleted(int transID, int respCode) {}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
四、直接操作蓝牙模块
1、使用AT指令
蓝牙模块通常支持AT指令集,通过串口通信发送AT指令来控制蓝牙模块。
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
int main() {
int fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY);
if (fd == -1) {
perror("Opening serial port failed");
return 1;
}
struct termios options;
tcgetattr(fd, &options);
cfsetispeed(&options, B9600);
cfsetospeed(&options, B9600);
options.c_cflag |= (CLOCAL | CREAD);
tcsetattr(fd, TCSANOW, &options);
char command[] = "AT+NAME?rn";
write(fd, command, strlen(command));
char response[100];
int n = read(fd, response, sizeof(response));
response[n] = '