modbus_rtu_set_custom_rts3
Set a function to be used for custom rts implementation
Usage
int modbus_rtu_set_custom_rts(modbus_t *ctx, void (set_rts) (modbus_t ctx, int on))
Overview
The modbus_rtu_set_custom_rts() function shall set a custom function to be called when the RTS pin is to be set before and after a transmission. By default this is set to an internal function that toggles the RTS pin using an ioctl call.
Note that this function adheres to the RTS mode, the values MODBUS_RTU_RTS_UP or MODBUS_RTU_RTS_DOWN must be used for the function to be called.
This function can only be used with a context using a RTU backend.
Return value
The modbus_rtu_set_custom_rts() function shall return 0 if successful. Otherwise it shall return -1 and set errno to one of the values defined below.
Errors
EINVAL
The libmodbus backend is not RTU.
Releases
3 releases since Debian 10 (Buster); the text changed 2 times.