Singleton: Difference between revisions

=={{header|C}}==

Since C doesn't really support classes anyhow, there's not much to do. If you want somethin akin to a singleton, what you do is first declare the interface functions in a header (.h) file.

<lang c>#ifndef SILLY_H

#define SILLY_H

extern void JumpOverTheDog( int numberOfTimes);

extern int PlayFetchWithDog( float weightOfStick);

#endif</lang>

Then in a separate C source (.c) file, define your structures, variables and functions.

<lang c>...

#include "silly.h"

struct sDog {

float max_stick_weight;

int isTired;

int isAnnoyed;

};

static struct sDog lazyDog = { 4.0, 0,0 };

/* define functions used by the functions in header as static */

static int RunToStick( )

{...

}

/* define functions declared in the header file.

void JumpOverTheDog(int numberOfTimes)

{ ...

}

int PlayFetchWithDog( float weightOfStick )

{ ...

}</lang>

Code using the singleton includes the header and cannot create a

struct sDog as the definition is only in the C source (or other header privately included by the silly.c source). Only the functions declared in the header may be used externally.