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External Delaration for An Array?

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Join Date: Jul 2008

Posts: 36

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lehe

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Light Poster

External Delaration for An Array?

Nov 20th, 2008

Hi,
I have an array. I put its definition in a .c file and externally delare it in a .h file like this:
//.c file
unsigned char jetmap[][]={
{0, 207, 255},
{0, 223, 255},
{0, 239, 255},
{0, 255, 255},
{16, 255, 239},
{32, 255, 223},
{48, 255, 207},
{64, 255, 191},
{80, 255, 175}
}
...
//.h file
extern unsigned char jetmap[][]; //missing subscript
// extern unsigned char ** jetmap; // redefinition; different types of indirection

As in the comment of the header file, both declarations are reported wrong by complier. How to delare the correct type of an array? Thanks in advance!

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Join Date: Sep 2004

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Narue

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Code Goddess

Re: External Delaration for An Array?

Nov 20th, 2008

>extern unsigned char jetmap[][]; //missing subscript
Yep, you're required to specify all but the first dimension, even for an incomplete type. You need it in the definition too:

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/* .c file */
unsigned char jetmap[][3] = { /* ... */ };
 
/* .h file */
extern unsigned char jetmap[][3];
/* .c file */
unsigned char jetmap[][3] = { /* ... */ };

/* .h file */
extern unsigned char jetmap[][3];

>extern unsigned char ** jetmap; // redefinition; different types of indirection
Yep, the declaration doesn't match the definition. The type of jetmap in the definition is unsigned char (*)[3] .

I'm here to prove you wrong.