Re: [cc65] Another wish: Unsized Arrays in Structures

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From: Spiro Trikaliotis (Trik-news_at_gmx.de)
Date: 2003-01-23 08:44:25 

Hello,

Groepaz wrote:

> On Wednesday 22 January 2003 23:37, Christian Krüger wrote:

> > today I've tried to compile something like this:
> >
> > --8<-------------------
> >
> > typedef struct
> > {
> >   unsigned char width;
> >   unsigned char height;
> >   unsigned char data[];
> > }
> > TestStruct;
> >
> > --8<-------------------

> why dont you simply use
>
>  typedef struct
>  {
>    unsigned char width;
>    unsigned char height;
>    unsigned char *data;
>  }
>  TestStruct;

Because it's not the same? ;-)

First: Christian, doesn't

   unsigned char data[0];

work as last element in CC65? If not, use it like David Holtz suggested
with index 1.

Groepaz: There is a difference. In your code, TestStruct contains
a pointer to some area. This is not true with Christian's wanted
solution.

Look at this:

TestStruct *a = malloc(sizeof(TestStruct)+sizeof(unsigned char)*100);

With this, you get a TestStruct which contains 100 elements (0..99)
[in case the 0 does not work, and David's suggestion has to be applied,
it is 101, ie., 0..100].

With your solution, you had to

TestStruct *a = malloc(sizeof(TestStruct));
a->data = malloc(sizeof(unsigned char)*100);

which is less handy than the first solution.

Spiro.

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