Added changes suggested by bug #3186 : fixing the unplugging of webcam

diff --git a/modules/highgui/src/cap_v4l.cpp b/modules/highgui/src/cap_v4l.cpp
index 045c6f8..49432c9 100644 (file)
--- a/modules/highgui/src/cap_v4l.cpp
+++ b/modules/highgui/src/cap_v4l.cpp
@@ -1236,10 +1236,10 @@ static int read_frame_v4l2(CvCaptureCAM_V4L* capture) {
    //set timestamp in capture struct to be timestamp of most recent frame
    capture->timestamp = buf.timestamp;
 
-   return 1;
+   return 2;
 }
 
-static void mainloop_v4l2(CvCaptureCAM_V4L* capture) {
+static int mainloop_v4l2(CvCaptureCAM_V4L* capture) {
     unsigned int count;
 
     count = 1;
@@ -1273,8 +1273,13 @@ static void mainloop_v4l2(CvCaptureCAM_V4L* capture) {
                 break;
             }
 
-            if (read_frame_v4l2 (capture))
-                break;
+            int readresult = read_frame_v412(capture);
+            if (readresult == 2){
+                return 0;
+            }
+            if (readresult){
+                return 1;
+            }
         }
     }
 }
@@ -1354,7 +1359,10 @@ static int icvGrabFrameCAM_V4L(CvCaptureCAM_V4L* capture) {
      {
         // skip first frame. it is often bad -- this is unnotied in traditional apps,
         //  but could be fatal if bad jpeg is enabled
-        mainloop_v4l2(capture);
+        if(!mainloop_v4l2(capture)){
+            fprintf( stderr, "HIGHGUI ERROR: V4L: Could not capture image.\n");
+            return 0;
+        }
      }
 #endif
 
@@ -1366,9 +1374,10 @@ static int icvGrabFrameCAM_V4L(CvCaptureCAM_V4L* capture) {
 
    if (V4L2_SUPPORT == 1)
    {
-
-     mainloop_v4l2(capture);
-
+        if(!mainloop_v4l2(capture)){
+            fprintf( stderr, "HIGHGUI ERROR: V4L: Could not capture image.\n");
+            return 0;
+        }
    }
 #endif /* HAVE_CAMV4L2 */
 #if defined(HAVE_CAMV4L) && defined(HAVE_CAMV4L2)