what extra changes i need to do when i make my local variable to global variable ?

Qt embedded developer

typedef struct
{
int nI2C;
unsigned char nAddress;
}TI2C;

TI2C i2c;
void *pHandle = (void*) & i2c;

qDebug("gauge test\n\r");

if((i2c.nI2C= open("/dev/i2c-2", O_RDWR))<0)
{
    qDebug("can not open I2C bus \n\r");
    return bStatus;
}

qDebug("openend I2C bus\n\r");

unsigned char nAddress=GAUGE_DEVICE_ADDRESS;

TI2C *pI2C= (TI2C*) pHandle;

if(nAddress!= pI2C->nAddress)
    ioctl(pI2C->nI2C,I2C_SLAVE,nAddress>>1);
else
{
    qDebug("Battery fuel gauge not found\n");
    return bStatus;
}
bStatus= true;
pI2C->nAddress= nAddress;
return bStatus;

i need below questions answer regarding above code.

1] what extra changes i need to do to make pI2C to make global structure pointer so that application not going to crash ?

2] what extra changes i need to do to make pHandle to make global structure pointer so that application not going to crash ?

jsulm

@Qt-embedded-developer Basics:

Make sure it is initialised (a pointer to valid instance assigned) before you use it
Same here

You should rething your design as global variables are usually a sign for bad design...

Qt embedded developer

@jsulm instead this which concept i need to use so i can make it to good design?

jsulm

@Qt-embedded-developer You should think about where these variables are really needed and keep them there (for example in a class which manages the access to them).

Qt embedded developer

@jsulm thanks !!