$ git clone https://github.com/yangfuyuan/sdk
$ cd sdk
$ git checkout master
$ cd ..
$ mkdir build
$ cd build
$ cmake ../sdk
$ make			###linux
$ vs open Project.sln	###windows

$ cd samples

$ ./ydlidar_test
$Lidar[ydlidar7] detected, whether to select current radar(yes/no)?:yes
0. 115200
1. 128000
2. 153600
3. 230400
4. 512000
$Please enter the lidar serial baud rate:2
0. false
1. true
$Please enter the lidar intensity:1

$ ydlidar_test.exe
$Lidar[ydlidar7] detected, whether to select current radar(yes/no)?:yes
0. 115200
1. 128000
2. 153600
3. 230400
4. 512000
$Please enter the lidar serial baud rate:2
0. false
1. true
$Please enter the lidar intensity:1

[YDLidar]: YDLidar running correctly ! The health status is good
[YDLIDAR] Connection established in [/dev/ttyUSB0]:
Firmware version: 1.2.0
Hardware version: 1
Model: S4
Serial: 2018091100006004
[YDLidar]: [YDLIDAR INFO] Current Sampling Rate : 4K
[YDLidar]: set EXPOSURE MODEL SUCCESS!!!
[YDLidar]: [YDLIDAR INFO] Now YDLIDAR is scanning ......

[YDLidar]: Scan received[1543834103116861000]: 498 ranges
[YDLidar]: Scan received[1543834103241414000]: 497 ranges
[YDLidar]: Scan received[1543834103468167000]: 497 ranges
[YDLidar]: Scan received[1543834103592417000]: 494 ranges

struct node_info {
	uint8_t    sync_flag;
	uint16_t   sync_quality;//!信号质量
	uint16_t   angle_q6_checkbit; //!测距点角度
	uint16_t   distance_q2; //! 当前测距点距离
	uint64_t   stamp; //! 时间戳
	uint8_t    scan_frequence;//! 特定版本此值才有效,无效值是0, 当前扫描频率current_frequence = scan_frequence/10.0
} __attribute__((packed)) ;

if(data[i].scan_frequence != 0) {
	current_frequence = data[i].scan_frequence/10.0;
}

current_time_stamp = data[i].stamp;

 if(m_isMultipleRate) {
	current_distance = (float)data[i].distance_q2/2000.f;
}else {
	current_distance = (float)data[i].distance_q2/4000.f;
}

current_angle = ((data[i].angle_q6_checkbit>>LIDAR_RESP_MEASUREMENT_ANGLE_SHIFT)/64.0f);

current_intensity = (float)(data[i].sync_quality >> LIDAR_RESP_MEASUREMENT_QUALITY_SHIFT);

###note:current_frequence = data[0].scan_frequence/10.0.

###if the current_frequence value equals zero, it is an invalid value.

    void ParseScan(node_info* data, const size_t& size) {

        double current_frequence, current_distance, current_angle, current_intensity;

        uint64_t current_time_stamp;

        for (size_t i = 0; i < size; i++ ) {

            if( data[i].scan_frequence != 0) {

                current_frequence =  data[i].scan_frequence;//or current_frequence = data[0].scan_frequence

            }

	 if(m_isMultipleRate) {
		current_distance = (float)data[i].distance_q2/2000.f;
	}else {
		current_distance = (float)data[i].distance_q2/4000.f;
	}

            current_angle = ((data[i].angle_q6_checkbit>>LIDAR_RESP_MEASUREMENT_ANGLE_SHIFT)/64.0f);//LIDAR_RESP_MEASUREMENT_ANGLE_SHIFT equals 8

            current_intensity = (float)(data[i].sync_quality >> LIDAR_RESP_MEASUREMENT_QUALITY_SHIFT);

        }

        if (current_frequence != 0 ) {

            printf("current lidar scan frequency: %f\n", current_frequence);

        } else {

            printf("Current lidar does not support return scan frequency\n");

        }
    }