From 46d620b27cb1d2d43da5d7b691c08db01177d0fa Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Wed, 13 Feb 2019 14:55:47 +0100 Subject: [PATCH] cansend: enhance help text for length info in RTR frames In 'classic' CAN 2.0 the RTR frames contain a length information in the can_dlc field of a CAN frame control section. This length can be passed to 'cansend' which has not been documented in the help text so far. Signed-off-by: Oliver Hartkopp --- cansend.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/cansend.c b/cansend.c index b912e80..b8baf58 100644 --- a/cansend.c +++ b/cansend.c @@ -75,11 +75,14 @@ int main(int argc, char **argv) required_mtu = parse_canframe(argv[2], &frame); if (!required_mtu){ fprintf(stderr, "\nWrong CAN-frame format! Try:\n\n"); - fprintf(stderr, " #{R|data} for CAN 2.0 frames\n"); + fprintf(stderr, " #{data} for 'classic' CAN 2.0 data frames\n"); + fprintf(stderr, " #R{len} for 'classic' CAN 2.0 RTR frames\n"); fprintf(stderr, " ##{data} for CAN FD frames\n\n"); fprintf(stderr, " can have 3 (SFF) or 8 (EFF) hex chars\n"); fprintf(stderr, "{data} has 0..8 (0..64 CAN FD) ASCII hex-values (optionally"); fprintf(stderr, " separated by '.')\n"); + fprintf(stderr, "{len} is an optional 0..8 value as RTR frames can contain a"); + fprintf(stderr, " valid dlc field\n"); fprintf(stderr, " a single ASCII Hex value (0 .. F) which defines"); fprintf(stderr, " canfd_frame.flags\n\n"); fprintf(stderr, "e.g. 5A1#11.2233.44556677.88 / 123#DEADBEEF / 5AA# / ");