From e0309946c0e29c6af012e0f5d9eed7f33b5866de Mon Sep 17 00:00:00 2001 From: "hans@rhel5-devel.localdomain" Date: Tue, 1 Sep 2009 10:03:27 +0200 Subject: [PATCH] libv4l: Document that passing in NULL as 3th arg to v4l2_ioctl is not allowed From: Hans de Goede libv4l: Document that passing in NULL as 3th arg to v4l2_ioctl is not allowed Priority: normal Signed-off-by: Hans de Goede --- lib/include/libv4l2.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/lib/include/libv4l2.h b/lib/include/libv4l2.h index 5488b2b..dfae214 100644 --- a/lib/include/libv4l2.h +++ b/lib/include/libv4l2.h @@ -51,6 +51,13 @@ LIBV4L_PUBLIC extern FILE *v4l2_log_file; Note the device name passed to v4l2_open must be of a video4linux2 device, if it is anything else (including a video4linux1 device), v4l2_open will fail. + + Note that the argument to v4l2_ioctl after the request must be a valid + memory address of structure of the appropriate type for the request (for + v4l2 requests which expect a structure address). Passing in NULL or an + invalid memory address will not lead to failure with errno being EFAULT, + as it would with a real ioctl, but will cause libv4l2 to break, and you + get to keep both pieces. */ LIBV4L_PUBLIC int v4l2_open (const char *file, int oflag, ...); -- 2.7.4