3 replies to this topic

[onus]

On this link
Linux/drivers/parport/parport_pc.c - Linux Cross Reference - Free Electrons
they defined a structure superio_struct and initialized as

superios[NR_SUPERIOS] = { {0,},};

I am not able to understand above initialization has what is it getting initialized to.

What I deduce till now is superios is a structure array of struct superio_struct
and NR_SUPERIOS is defined as 3 hence an array of structure of size 3
but

superios[0]=??

superios[1]=??

superios[2]=??

This part is not clear to me as to what these individual members are initialized to.

[mnirahd]

Hi,

Look at the definition of the identifier

 #define NR_SUPERIOS 3

 static struct superio_struct {  /* For Super-IO chips autodetection */

        int io;

        int irq;

        int dma;

} superios[NR_SUPERIOS] = { {0,},};

The above definition does the following

1. Declares a structured named superio_struct & declares array of that structure of size 3
2. The initialization array that all of the elements in structure array are initialized to 0.

So they are initialized as similarly as following,

superios[0]={0, 0 , 0};

superios[1]={0, 0 , 0};


superios[2]={0, 0 , 0};

I hope that it helps

Munir

[onus]

No I could not understand how is that getting initialized to zero.

[mnirahd]

Hi

superios[NR_SUPERIOS] = { {0,},};

This way declaring the array to size of 3, and initializing the first element in following way
superios[0].io = 0;

Now look at

superios[NR_SUPERIOS] = { {2,},};

this initializes the first element of the array to 2 like

superios[0].io = 2;

rest of the part of the array is being initialized to 0.

Munir