1、收先安装gtk3，我的测试机器是ubutn16.04，只要执行下面的安装命令就可以了
    apt-get install libgtk-3-dev
    使用下列命令验证是否安装好gtk3：
    pkg-config --cflags --libs gtk+-3.0
 2、显示结果类似如下：
    -pthread -I/usr/include/gtk-3.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/at-spi-2.0 -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-linux-gnu/dbus-1.0/include -I/usr/include/gtk-3.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/mirclient -I/usr/include/mircore -I/usr/include/mircookie -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng12 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0说明gtk3可以使用了。
3、文件名：“enquire_camera.c” 代码如下：

#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <zconf.h>
#include <linux/videodev2.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <gtk-3.0/gtk/gtk.h>

//dhl:gtk窗口组件
GtkWidget *window;
GtkWidget *fixed;
GtkWidget *button1,*button2;
GtkWidget *text,*text1,*text2,*text3;
GtkTextBuffer *buffer,*buffer1,*buffer2,*buffer3;
GtkWidget *label1,*label2,*label3,*label_line;

//dhl:消息缓存
char disp[2048]={0};
char temp[128]={0};


//dhl:发现摄像头
void button1_clicked(GtkWidget *widget, gpointer data)
{
	char camera_devices_name[128]={0};
	for (int loop=0;loop<10;loop++) {
		sprintf(camera_devices_name,"/dev/video%d",loop);
		int fd = open(camera_devices_name, O_RDWR);
		if(fd < 0)
		{
			printf("打开设备失败(%s)\n",camera_devices_name);
			close(fd);
			continue;
		}
	    close(fd);
		sprintf(temp,"发现摄像头:%s\n",camera_devices_name);
		strcat(disp,temp);
		gtk_text_buffer_set_text(buffer,disp,-1);
	}
	sprintf(disp,"%s","");
}

//dhl:查询配置信息
void button2_clicked(GtkWidget *widget, gpointer data)
{
	int line_num=0;
	gchar *device_name;
	GtkTextIter start,end;
	gtk_text_buffer_get_bounds(GTK_TEXT_BUFFER(buffer1),&start,&end);
	const GtkTextIter s=start,e=end;
	device_name=gtk_text_buffer_get_text(GTK_TEXT_BUFFER(buffer1),&s,&e,FALSE);
	if (!strcmp(device_name,""))
	{
		sprintf(temp,"请输入摄像头设备文件名\n");
		strcat(disp,temp);
		gtk_text_buffer_set_text(buffer,disp,-1);
		sprintf(disp,"%s","");
		return;
	}
		
		
	//dhl:查询摄像头支持的视频格式
	int fd = open(device_name, O_RDWR);
	if(fd < 0)
	{
		printf("打开设备失败\n");
		return;
	}

	struct v4l2_fmtdesc v4fmt;
	v4fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; //视频捕获设备
	int i=0;

	while(1)
	{
		v4fmt.index = i++;
		int ret = ioctl(fd, VIDIOC_ENUM_FMT, &v4fmt);
		if(ret < 0)
		{
			printf("获取摄像头格式失败");
			break;
		}
		printf("index=%d\n", v4fmt.index);
		printf("flags=%d\n", v4fmt.flags);
		printf("description=%s\n", v4fmt.description);
		unsigned char *p = (unsigned char *)&v4fmt.pixelformat;
		printf("pixelformat=%c%c%c%c\n", p[0],p[1],p[2],p[3]);
		printf("reserved=%d\n", v4fmt.reserved[0]);
		
		sprintf(temp,"摄像头支持的视频格式(%d)\n",i);
		strcat(disp,temp);
		
		sprintf(temp,"index=%d,", v4fmt.index);
		strcat(disp,temp);
		
		sprintf(temp,"flags=%d,", v4fmt.flags);
		strcat(disp,temp);
		
		sprintf(temp,"description=%s,", v4fmt.description);
		strcat(disp,temp);
		
		sprintf(temp,"pixelformat=%c%c%c%c,", p[0],p[1],p[2],p[3]);
		strcat(disp,temp);
		
		sprintf(temp,"reserved=%d\n", v4fmt.reserved[0]);
		strcat(disp,temp);
		
	}
	
	close(fd);
	
	//dhl:MJPG支持的所有分辨率如下
	fd = open(device_name, O_RDWR);
	if(fd < 0)
	{
		perror("打开设备失败");
		return;
	}
	struct v4l2_frmsizeenum frmsize;
	frmsize.index = 0;
	frmsize.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	printf("MJPEG格式支持所有分辨率如下:\n");
	//frmsize.pixel_format = V4L2_PIX_FMT_YUYV;
	frmsize.pixel_format = V4L2_PIX_FMT_MJPEG;
	sprintf(temp,"MJPG支持的分辨率:\n");
	strcat(disp,temp);
	line_num=1;
	while(ioctl(fd,VIDIOC_ENUM_FRAMESIZES,&frmsize) == 0){
		printf("frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);
		frmsize.index++;
		if ((line_num % 5) != 0) { 
			sprintf(temp,"MJPEG frame_size<%d*%d>, ",frmsize.discrete.width,frmsize.discrete.height);
		}else {
			sprintf(temp,"MJPEG frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);
		}
		strcat(disp,temp);
		line_num++;
		if (line_num == 6) {
			line_num = 1;
		}
	}
	close(fd);
	sprintf(temp,"%s","\n");
	strcat(disp,temp);
	
	
	//dhl:YUV支持所有分辨率如下
	fd = open(device_name, O_RDWR);
	if(fd < 0)
	{
		perror("打开设备失败");
		return;
	}
	//struct v4l2_frmsizeenum frmsize;
	frmsize.index = 0;
	frmsize.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	printf("MJPEG格式支持所有分辨率如下:\n");
	frmsize.pixel_format = V4L2_PIX_FMT_YUYV;
	//frmsize.pixel_format = V4L2_PIX_FMT_MJPEG;
	sprintf(temp,"YUV支持的分辨率:\n");
	strcat(disp,temp);
	line_num = 1;
	while(ioctl(fd,VIDIOC_ENUM_FRAMESIZES,&frmsize) == 0){
		printf("frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);
		frmsize.index++;
		if ((line_num % 5) != 0) { 
			sprintf(temp,"YUYV frame_size<%d*%d>, ",frmsize.discrete.width,frmsize.discrete.height);
		}else {
			sprintf(temp,"YUYV frame_size<%d*%d>\n",frmsize.discrete.width,frmsize.discrete.height);
			
		}
		strcat(disp,temp);
		line_num++;
		if (line_num == 6) {
			line_num = 1;
		}
	}
	
	close(fd);
	
	
	gtk_text_buffer_set_text(buffer,disp,-1);
	sprintf(disp,"%s","");
	
}


int main(int argc,char *argv[])
{
	gtk_init(&argc,&argv);
    
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(GTK_WINDOW(window),"USB摄像头测试程序(v1.0.20230728)");
    //gtk_window_set_resizable(GTK_WINDOW(window),FALSE);
    gtk_window_set_default_size(GTK_WINDOW(window),1280,800);
    gtk_window_set_position(GTK_WINDOW(window),GTK_WIN_POS_CENTER);
	
    fixed = gtk_fixed_new();
    gtk_container_add(GTK_CONTAINER(window),fixed);
    
    text = gtk_text_view_new();
    buffer=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text));
    gtk_text_buffer_set_text(buffer,"",-1);
    gtk_fixed_put(GTK_FIXED(fixed),text,20,480);
    gtk_widget_set_size_request(text,1240,300);
    
    button1 = gtk_button_new_with_label("查询摄像头");
    gtk_fixed_put(GTK_FIXED(fixed),button1,320,14);
    gtk_widget_set_size_request(button1,100,20);
    
    label1 = gtk_label_new("摄像头：");
    gtk_fixed_put(GTK_FIXED(fixed),label1,440,14);
    gtk_widget_set_size_request(label1,50,30);
    
    text1 = gtk_text_view_new();
    buffer1=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text1));
    gtk_text_buffer_set_text(buffer1,"",-1);
    gtk_fixed_put(GTK_FIXED(fixed),text1,500,16);
    gtk_widget_set_size_request(text1,100,28);
    sprintf(disp,"/dev/video0");
	gtk_text_buffer_set_text(buffer1,disp,-1);
    
    button2 = gtk_button_new_with_label("查询配置");
    gtk_fixed_put(GTK_FIXED(fixed),button2,610,14);
    gtk_widget_set_size_request(button2,80,35);
    
    
    label2 = gtk_label_new("分辨率：");
    gtk_fixed_put(GTK_FIXED(fixed),label2,740,18);
    gtk_widget_set_size_request(label2,50,30);
    text2 = gtk_text_view_new();
    buffer2=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text2));
    gtk_text_buffer_set_text(buffer2,"",-1);
    gtk_fixed_put(GTK_FIXED(fixed),text2,800,16);
    gtk_widget_set_size_request(text2,100,28);
    sprintf(disp,"640x480");
	gtk_text_buffer_set_text(buffer2,disp,-1);
    
    
    label3 = gtk_label_new("帧率：");
    gtk_fixed_put(GTK_FIXED(fixed),label3,930,18);
    gtk_widget_set_size_request(label3,50,30);
    text3 = gtk_text_view_new();
    buffer3=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text3));
    gtk_text_buffer_set_text(buffer3,"",-1);
    gtk_fixed_put(GTK_FIXED(fixed),text3,980,16);
    gtk_widget_set_size_request(text3,100,28);
    sprintf(disp,"30");
	gtk_text_buffer_set_text(buffer3,disp,-1);

   
    g_signal_connect_swapped(G_OBJECT(window),"destroy",G_CALLBACK(gtk_main_quit),NULL);
    g_signal_connect(G_OBJECT(button1), "clicked", G_CALLBACK(button1_clicked),NULL);
    g_signal_connect(G_OBJECT(button2), "clicked", G_CALLBACK(button2_clicked),NULL);
   
    
    gtk_widget_show_all(window);
    gtk_main();

    return 0;
}

4、编译命令：gcc enquire_camera.c  -o camera_enquire  `pkg-config --cflags --libs gtk+-3.0` -w

5、运行 “./camera_enquire”
6、运行结果：