MODBUS_SET_ERROR_REC(3) Libmodbus Manual MODBUS_SET_ERROR_REC(3)NAME
modbus_set_error_recovery - set the error recovery mode
SYNOPSIS
int modbus_set_error_recovery(modbus_t *ctx, modbus_error_recovery_mode error_recovery);
DESCRIPTION
The modbus_set_error_recovery() function shall set the error recovery mode to apply when the connection fails or the byte received is not
expected. The argument error_recovery may be bitwise-or'ed with zero or more of the following constants.
By default there is no error recovery (MODBUS_ERROR_RECOVERY_NONE) so the application is responsible for controlling the error values
returned by libmodbus functions and for handling them if necessary.
When MODBUS_ERROR_RECOVERY_LINK is set, the library will attempt an immediate reconnection (which may hang for several seconds if the
network to the remote target unit is down). This mode will try a infinite close/connect loop until success on send call and will just try
one time to retablish the connection on select/read calls (if the connecton was down, the values to read are certainly not available
anymore after reconnection, except for slave/server). This mode will also run flush requests after a delay based on the current response
timeout in some situations (eg. timeout of select call).
When MODBUS_ERROR_RECOVERY_PROTOCOL is set, a sleep and flush sequence will be used to cleanup the ongoing communication, this can occurs
when the message length is invalid, the TID is wrong or the received function code is not the expected one.
The modes are mask values and so they are complementary.
It's not recommended to enable error recovery for slave/server.
RETURN VALUE
The modbus_set_error_recovery() function shall return 0 if successful. Otherwise it shall return -1 and set errno to one of the values
defined below.
ERRORS
EINVAL
The value of the argument error_recovery is not positive.
EXAMPLE
modbus_set_error_recovery(ctx,
MODBUS_ERROR_RECOVERY_LINK |
MODBUS_ERROR_RECOVERY_PROTOCOL);
AUTHORS
The libmodbus documentation was written by Stephane Raimbault <stephane.raimbault@gmail.com[1]>
NOTES
1. stephane.raimbault@gmail.com
mailto:stephane.raimbault@gmail.com
libmodbus 3.0.3 05/26/2012 MODBUS_SET_ERROR_REC(3)
Check Out this Related Man Page
RFCOMM_SPPD(1) BSD General Commands Manual RFCOMM_SPPD(1)NAME
rfcomm_sppd -- RFCOMM Serial Port Profile daemon
SYNOPSIS
rfcomm_sppd [-bhtS] -a address -c channel
DESCRIPTION
The rfcomm_sppd utility is a Serial Port Profile daemon. It can operate in two modes: client and server.
In client mode, rfcomm_sppd opens RFCOMM connection to the specified address server and channel. Once connection is established, the
rfcomm_sppd utility provides access to the server's remote serial port via stdin/stdout or via pts(4) interface if -t option was specified.
If the -S option is specified, rfcomm_sppd will operate in server mode and act as RFCOMM server, listening on ANY address and advertising a
virtual serial port via the sdpd(8) daemon. If -t options was specified, the server side of the virtual serial port is attached to a pseudo-
terminal. Otherwise the virtual serial port is attached to the stdin/stdout. rfcomm_sppd should be run as root in order to communicate with
sdpd(8) in this case.
The rfcomm_sppd utility opens both master and slave pseudo terminals. This is done to ensure that RFCOMM connection stays open until
rfcomm_sppd is terminated. The data received from the master pseudo terminal are sent over the RFCOMM connection. The data received from
the RFCOMM connection are written into master pseudo terminal. The application in its turn opens the slave pseudo terminal and operates on
it just like it would operate over the standard serial port.
The options are as follows:
-a address
In client mode, this required option specifies the address of the remote RFCOMM server. If this option is specified in server mode,
rfcomm_sppd will only accept connections from the Bluetooth device with address address. The address can be specified as BD_ADDR or
name. If name was specified then rfcomm_sppd utility will attempt to resolve the name via bt_gethostbyname(3).
-b Detach from the controlling terminal, i.e., run in background.
-c channel
In both client and server mode, this option specifies the RFCOMM channel to connect to or listen on. In server mode, the channel
should be a number between 1 and 30. If not specified, rfcomm_sppd will try to bind to ``wildcard'' RFCOMM channel number. The
actual RFCOMM channel will be obtained via getsockname(2) call and will be used to register Serial Port service with sdpd(8). In
client mode, the channel could either be a number between 1 and 30 or a service name. Supported service names are: DUN (for DialUp
Networking service), FAX (for Fax service), LAN (for LAN Access Using PPP service) and SP (for Serial Port service). If channel was
not specified then rfcomm_sppd utility will try to obtain RFCOMM channel for Serial Port service via Service Discovery Protocol from
the server.
-h Display usage message and exit.
-S Server mode; see DESCRIPTION.
-t Use slave pseudo tty. If not set stdin/stdout will be used. This option is required if -b option was specified.
FILES
/dev/pts/[num] slave pseudo terminals
EXIT STATUS
The rfcomm_sppd utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
rfcomm_sppd -a 00:01:02:03:04:05 -c 1 -t
Will start the rfcomm_sppd utility and open RFCOMM connection to the server at 00:01:02:03:04:05 and channel 1. Once the connection has been
established, a pts(4) can be used to talk to the remote serial port on the server. rfcomm_sppd prints the name of the pts(4) to use on std-
out.
SEE ALSO bluetooth(3), ng_btsocket(4), pts(4), rfcomm_pppd(8), sdpd(8)AUTHORS
Maksim Yevmenkin <m_evmenkin@yahoo.com>
BUGS
Please report if found.
BSD April 21, 2008 BSD