RS485 compile errors

#include "RS485_non_blocking.h"
#include <SoftwareSerial.h>

const byte ENABLE_PIN=4;
const byte LED_PIN=13;


SoftwareSerial rs485(2,3);


// callback routines
void fWrite( const byte what ){
  rs485.print(what);
}
int fAvailable(){
  return rs485.available();
}
int fRead(){
  return rs485.read();
}


void setup(){
  rs485.begin(28800); //28.8kbaud!
  pinMode( ENABLE_PIN, OUTPUT );
  pinMode( LED_PIN, OUTPUT );
}

byte old_level=0;

void loop(){
  // read potentiometer
  byte level=analogRead(0)/4;  // (scales 0-1023 down to 0-254)
  
  // no change in level, no transmit
  if ( level == old_level ){
    return;
  }
  
  byte msg[] = { // I think this is the protocol right here...
    1,    // Device 1
    2,    // Turn light on
    level // to what level
  };
  
  // send to slave
  digitalWrite( ENABLE_PIN, HIGH); // enable sending
  sendMsg ( fWrite, msg, sizeof msg );
  digitalWrite( ENABLE_PIN, LOW);  // disable sending
  
  // receive response
  byte buf[10];
  byte received = recvMsg( fAvailable, fRead, buf, sizeof buf);
  digitalWrite(LED_PIN, received==0); // turn on LED if error
  
  // only send once per successful change
  if ( received ){
    old_level = level;
  }
}

RS485_General__1.cpp: In function 'void loop()':
RS485_General__1:47: error: 'sendMsg' was not declared in this scope
RS485_General__1:52: error: 'recvMsg' was not declared in this scope