Is it OK having only .h file in user' library , no .cpp ?

Projects Programming
1

Hello, I just want to confirm with others that it is OK to create a user library with only .h file in it. The purpose is obviously to have custom include file shared by many sketches.
The process of building the project looks somewhat different:
when compiling libraries , compiler only says "Using library blablabla.h ..." but no compiler running for this library. In the end everything is built and linked .
Tried this in Arduino IDE and Visual Studio + vMicro - both work.

Please let me know that I am not missing something to be surprised in he future :slight_smile:
Vladimir

2

What's in the .h file. Post it.

Mark

3

This is a shortened file version as it is rather large. The rest is similar definition types.

/**********************************************

  • In-Flight Controller Definitions
    ***********************/
    #ifndef IFC_H
    #define IFC_H
    /     List of Global Defines ******************/

#define SD_PRESENT // include SD card support
#define IFC_BATTERY
#define THRUST
#define AVIONICS
//#define DEBUG_AVIONICS

/************************* AVIONICS *********************************/
#define AVIO_PIN 47 // SS pin to control avionics module

#define SEA_LEVEL_PRESSURE 1014 // in hPa updated using buttons in IFC Setup screen
// integer is fine as it must be stored in EEPROM
#define REF_ALTITUDE 100 // reference altitude in ft, updated in IFC Setup screen,
// integer is fine as it must be stored in EEPROM
#define TOP_SPEED 800 // in mph linear ratio calibration... updated in Setup

/********************************************************************/
const byte AVIO_WRITE_SETUP = 11; // write setup variables to Avionics module
const byte AVIO_READ_DATA = 12; // read Avio data from avionics module
const byte AVIO_READ_SETUP = 13; // read Avio setup for debug confirmation

//typedef struct AVIO_SETUP
struct AVIO_SETUP
{
int slp; // sea level pressure in hPa was setup in Setup screen
int refAlt; // reference Altitude in ft was setup in Setup screen
int top_speed; // top speed for calibration in mph from setup screen
byte calibrate; // '1' means read averaged airspeed calibration code and store in EEPROM,
// '0' means no calibration
// int speed_0_code; // code read for speed 0 event triggered from setup button
};

//typedef struct AVIO_GET_DATA
struct AVIO_GET_DATA
{
int absAlt; // in ft from Avionics module
int relAlt; // relative Altitude in ft, could be negative
int vario; // ft per min in US units, could be negative
int airspeed; // true adjusted airspeed reading mph
};

#endif IFC_H

It is a "pure" include file with definitions.
Vlad

4

It is a "pure" include file with definitions.

Then there would be nothing to put in a .cpp file. So, you don't need one.

That would be different if you were actually implementing functions in the header file.

5

But if I put in-line functions, I could still have only .h file , is it so?

6

eBirdman:
But if I put in-line functions, I could still have only .h file , is it so?

No. If you implement functions, the implementation belongs in a source file.

While you can sometimes get away with implementing functions in a header file, there will be someone, somewhere, that can't use your library because you have done that. So, don't do that.

7

Thank you very much for your help
Sincerely
Vlad