is pid display futil ?

v4l2/grabvidseq.c

@@ -145,7 +145,7 @@ for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
 				fd, buf.m.offset);
 
 	if (MAP_FAILED == buffers[n_buffers].start) {
-		perror("mmap");
+		perror("v4l2_mmap");
 		exit(EXIT_FAILURE);
 		}
 	}
@@ -163,7 +163,8 @@ for (i = 0; i < n_buffers; ++i) {
 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 xioctl(fd, VIDIOC_STREAMON, &type);
 
-if (verbosity)	fprintf(stderr,"pid %d grabbing...\n", getpid());
+if (verbosity)	fprintf(stderr,"pid %d grabbing %d picz...\n",
+					getpid(), nbre_capt);
 
 for (i = 0; i < nbre_capt; i++) {
 	do	{
@@ -208,7 +209,7 @@ for (i = 0; i < nbre_capt; i++) {
 }
 
 t_final = fimg_timer_get(0);
-fprintf(stderr, "elapsed time %g s\n", t_final);
+fprintf(stderr, "pid %d : elapsed time %g s\n", getpid(), t_final);
 
 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 xioctl(fd, VIDIOC_STREAMOFF, &type);