modbus_rtu_set_custom_rts(3) ============================ NAME ---- modbus_rtu_set_custom_rts - set a function to be used for custom RTS implementation SYNOPSIS -------- *int modbus_rtu_set_custom_rts(modbus_t *'ctx', void (*'set_rts') (modbus_t *ctx, int on))* DESCRIPTION ----------- 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. AUTHORS ------- Jimmy Bergström The libmodbus documentation was written by Stéphane Raimbault