I have a CanUtils.h header file and a CanUtils.cpp source file, organized in the following directory tree:
Documents
|---Arduino
| |---libraries
| |--- CanUtils
| |--- CanUtils.h
|--- CanUtils.cpp
These files make up the CanUtils library I'm trying to create. The contents of CanUtils.h are as follows:
#ifndef CanUtils_h
#define CanUtils_h
enum PRIORITY_LEVEL
{
LOW = 6
};
#endif
While the contents of CanUtils.cpp are as follows:
#include "CanUtils.h"
As you can see, it is really simple, but when I just try to include the library using the following test script:
#include <CanUtils.h>
void setup() {
// put your setup code here, to run once:
}
void loop() {
// put your main code here, to run repeatedly:
}
I get the following error log after compiling:
In file included from C:\AppData\Local\Temp\arduino\sketches\FB4D0CAE5653D98D753CBC42EE69409D\sketch\library_tests.ino.cpp:1:0: C:AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:41:14: error: expected identifier before numeric constant #define LOW 0x0 ^ C:\Documents\Arduino\libraries\CanUtils/CanUtils.h:7:3: note: in expansion of macro 'LOW' LOW = 6 ^~~ C:\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:41:14: error: expected '}' before numeric constant #define LOW 0x0 ^ C:\Documents\Arduino\libraries\CanUtils/CanUtils.h:7:3: note: in expansion of macro 'LOW' LOW = 6 ^~~ C:\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:41:14: error: expected unqualified-id before numeric constant #define LOW 0x0 ^ C:\Documents\Arduino\libraries\CanUtils/CanUtils.h:7:3: note: in expansion of macro 'LOW' LOW = 6 ^~~ In file included from C:\Users\PC-LENOVO\Downloads\library_tests\library_tests.ino:1:0: C:\Documents\Arduino\libraries\CanUtils/CanUtils.h:8:1: error: expected declaration before '}' token }; ^
exit status 1
Compilation error: exit status 1//i.sstatic.net/EbLqZ.png
I'm not sure where the error can be...From the error log it looks like there's gotta be some sort of macro definition clash with a core Arduino library when attempting to use the keyword "LOW" in an enum. Going to that same file indicated by the error log shows there is a definition in Arduino.h for the keyword LOW:
/*
Arduino.h - Main include file for the Arduino SDK
Copyright (c) 2005-2013 Arduino Team. All right reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef Arduino_h
#define Arduino_h
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <math.h>
#include <avr/pgmspace.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include "binary.h"
#ifdef __cplusplus
extern "C"{
#endif
void yield(void);
#define HIGH 0x1
#define LOW 0x0
#define INPUT 0x0
#define OUTPUT 0x1
#define INPUT_PULLUP 0x2
#define PI 3.1415926535897932384626433832795
#define HALF_PI 1.5707963267948966192313216916398
#define TWO_PI 6.283185307179586476925286766559
#define DEG_TO_RAD 0.017453292519943295769236907684886
#define RAD_TO_DEG 57.295779513082320876798154814105
#define EULER 2.718281828459045235360287471352
#define SERIAL 0x0
#define DISPLAY 0x1
#define LSBFIRST 0
#define MSBFIRST 1
#define CHANGE 1
#define FALLING 2
#define RISING 3
#if defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
#define DEFAULT 0
#define EXTERNAL 1
#define INTERNAL1V1 2
#define INTERNAL INTERNAL1V1
#elif defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
#define DEFAULT 0
#define EXTERNAL 4
#define INTERNAL1V1 8
#define INTERNAL INTERNAL1V1
#define INTERNAL2V56 9
#define INTERNAL2V56_EXTCAP 13
#else
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega644__) || defined(__AVR_ATmega644A__) || defined(__AVR_ATmega644P__) || defined(__AVR_ATmega644PA__)
#define INTERNAL1V1 2
#define INTERNAL2V56 3
#else
#define INTERNAL 3
#endif
#define DEFAULT 1
#define EXTERNAL 0
#endif
// undefine stdlib's abs if encountered
#ifdef abs
#undef abs
#endif
#define min(a,b) ((a)<(b)?(a):(b))
#define max(a,b) ((a)>(b)?(a):(b))
#define abs(x) ((x)>0?(x):-(x))
#define constrain(amt,low,high) ((amt)<(low)?(low):((amt)>(high)?(high):(amt)))
#define round(x) ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))
#define radians(deg) ((deg)*DEG_TO_RAD)
#define degrees(rad) ((rad)*RAD_TO_DEG)
#define sq(x) ((x)*(x))
#define interrupts() sei()
#define noInterrupts() cli()
#define clockCyclesPerMicrosecond() ( F_CPU / 1000000L )
#define clockCyclesToMicroseconds(a) ( (a) / clockCyclesPerMicrosecond() )
#define microsecondsToClockCycles(a) ( (a) * clockCyclesPerMicrosecond() )
#define lowByte(w) ((uint8_t) ((w) & 0xff))
#define highByte(w) ((uint8_t) ((w) >> 8))
#define bitRead(value, bit) (((value) >> (bit)) & 0x01)
#define bitSet(value, bit) ((value) |= (1UL << (bit)))
#define bitClear(value, bit) ((value) &= ~(1UL << (bit)))
#define bitToggle(value, bit) ((value) ^= (1UL << (bit)))
#define bitWrite(value, bit, bitvalue) ((bitvalue) ? bitSet(value, bit) : bitClear(value, bit))
// avr-libc defines _NOP() since 1.6.2
#ifndef _NOP
#define _NOP() do { __asm__ volatile ("nop"); } while (0)
#endif
typedef unsigned int word;
#define bit(b) (1UL << (b))
typedef bool boolean;
typedef uint8_t byte;
void init(void);
void initVariant(void);
int atexit(void (*func)()) __attribute__((weak));
void pinMode(uint8_t pin, uint8_t mode);
void digitalWrite(uint8_t pin, uint8_t val);
int digitalRead(uint8_t pin);
int analogRead(uint8_t pin);
void analogReference(uint8_t mode);
void analogWrite(uint8_t pin, int val);
unsigned long millis(void);
unsigned long micros(void);
void delay(unsigned long ms);
void delayMicroseconds(unsigned int us);
unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout);
unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout);
void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val);
uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder);
void attachInterrupt(uint8_t interruptNum, void (*userFunc)(void), int mode);
void detachInterrupt(uint8_t interruptNum);
void setup(void);
void loop(void);
// Get the bit location within the hardware port of the given virtual pin.
// This comes from the pins_*.c file for the active board configuration.
#define analogInPinToBit(P) (P)
// On the ATmega1280, the addresses of some of the port registers are
// greater than 255, so we can't store them in uint8_t's.
extern const uint16_t PROGMEM port_to_mode_PGM[];
extern const uint16_t PROGMEM port_to_input_PGM[];
extern const uint16_t PROGMEM port_to_output_PGM[];
extern const uint8_t PROGMEM digital_pin_to_port_PGM[];
// extern const uint8_t PROGMEM digital_pin_to_bit_PGM[];
extern const uint8_t PROGMEM digital_pin_to_bit_mask_PGM[];
extern const uint8_t PROGMEM digital_pin_to_timer_PGM[];
// Get the bit location within the hardware port of the given virtual pin.
// This comes from the pins_*.c file for the active board configuration.
//
// These perform slightly better as macros compared to inline functions
//
#define digitalPinToPort(P) ( pgm_read_byte( digital_pin_to_port_PGM + (P) ) )
#define digitalPinToBitMask(P) ( pgm_read_byte( digital_pin_to_bit_mask_PGM + (P) ) )
#define digitalPinToTimer(P) ( pgm_read_byte( digital_pin_to_timer_PGM + (P) ) )
#define analogInPinToBit(P) (P)
#define portOutputRegister(P) ( (volatile uint8_t *)( pgm_read_word( port_to_output_PGM + (P))) )
#define portInputRegister(P) ( (volatile uint8_t *)( pgm_read_word( port_to_input_PGM + (P))) )
#define portModeRegister(P) ( (volatile uint8_t *)( pgm_read_word( port_to_mode_PGM + (P))) )
#define NOT_A_PIN 0
#define NOT_A_PORT 0
#define NOT_AN_INTERRUPT -1
#ifdef ARDUINO_MAIN
#define PA 1
#define PB 2
#define PC 3
#define PD 4
#define PE 5
#define PF 6
#define PG 7
#define PH 8
#define PJ 10
#define PK 11
#define PL 12
#endif
#define NOT_ON_TIMER 0
#define TIMER0A 1
#define TIMER0B 2
#define TIMER1A 3
#define TIMER1B 4
#define TIMER1C 5
#define TIMER2 6
#define TIMER2A 7
#define TIMER2B 8
#define TIMER3A 9
#define TIMER3B 10
#define TIMER3C 11
#define TIMER4A 12
#define TIMER4B 13
#define TIMER4C 14
#define TIMER4D 15
#define TIMER5A 16
#define TIMER5B 17
#define TIMER5C 18
#ifdef __cplusplus
} // extern "C"
#endif
#ifdef __cplusplus
#include "WCharacter.h"
#include "WString.h"
#include "HardwareSerial.h"
#include "USBAPI.h"
#if defined(HAVE_HWSERIAL0) && defined(HAVE_CDCSERIAL)
#error "Targets with both UART0 and CDC serial not supported"
#endif
uint16_t makeWord(uint16_t w);
uint16_t makeWord(byte h, byte l);
#define word(...) makeWord(__VA_ARGS__)
unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout = 1000000L);
unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout = 1000000L);
void tone(uint8_t _pin, unsigned int frequency, unsigned long duration = 0);
void noTone(uint8_t _pin);
// WMath prototypes
long random(long);
long random(long, long);
void randomSeed(unsigned long);
long map(long, long, long, long, long);
#endif
#include "pins_arduino.h"
#endif
Is there any way to circumvent this problem?
"Keywords are constants, variables and function names that are defined as part of the Arduino language. Avoid using keywords for variable names." (extracted from: https://ccrma.stanford.edu/~fgeorg/250a/lab2/arduino-0019/reference/Keywords.html). It turns out "LOW" is one of those keywords...