Array has incomplete element type. GCC bug?

[arcadio]

Hi everyone,

I'm currently struggling to compile a large piece of legacy code. GCC
3.3 compiles it without complaining, but GCC 4.2.3 (the default in
Debian) refuses it and signals "several array has incomplete element
type" errors.

I know that since 4.0 or so, GCC is less forgiving and does not accept
any arrays of incomplete type (see http://gcc.gnu.org/ml/gcc/2005-02/msg00053.html).
However, I cannot see where the array types are incomplete here:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char [][], const int, const int,
const int, const int y);

/* From the source: ERROR: Array type has incomplete element type */
void grphcs_enhnc_ou tsquare(unsigne d char outsquare[][], const int w,
const int h, const int x, const int y)
{ /* ... */ }

/* From another header */
extern void bz_comp(int, int [], int [], int [], int *, int [][], int
*[]);

/* From the corresponding source: ERROR: Array type has incomplete
element type */
void bz_comp(
int npoints,
int xcol[ MAX_BOZORTH_MIN UTIAE ],
int ycol[ MAX_BOZORTH_MIN UTIAE ],
int thetacol[ MAX_BOZORTH_MIN UTIAE ],

int * ncomparisons,
int cols[][ COLS_SIZE_2 ],
int * colptrs[]
)
{ /* ... */ }
Can anyone shed some light?

Thanks in advance
- Arcadio

[Lew Pitcher]

In comp.lang.c, arcadio wrote:

Hi everyone,

I'm currently struggling to compile a large piece of legacy code. GCC
3.3 compiles it without complaining, but GCC 4.2.3 (the default in
Debian) refuses it and signals "several array has incomplete element
type" errors.

[snip]

/* From the corresponding source: ERROR: Array type has incomplete
element type */
void bz_comp(
int npoints,
int xcol[ MAX_BOZORTH_MIN UTIAE ],
int ycol[ MAX_BOZORTH_MIN UTIAE ],
int thetacol[ MAX_BOZORTH_MIN UTIAE ],

int * ncomparisons,
int cols[][ COLS_SIZE_2 ],

How many cols elements are in this array? How can the compiler determine
that number?

int * colptrs[]
)
{ /* ... */ }
Can anyone shed some light?

Thanks in advance
- Arcadio

--
Lew Pitcher

Master Codewright & JOAT-in-training | Registered Linux User #112576
http://pitcher.digitalfreehold.ca/ | GPG public key available by request
---------- Slackware - Because I know what I'm doing. ------

[Richard Heathfield]

arcadio said:

<snip>

However, I cannot see
where the array types are incomplete here:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char [][]

^^^^
Right here.

Regarding your subject line, "Array has incomplete element type. GCC bug?",
it is generally wisest in the first instance[1] to assume that the bug is
in your code unless you can demonstrate from the Standard that your code
is correct.

[1]...and the second instance, and the third...

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[pete]

arcadio wrote:

Hi everyone,

I'm currently struggling to compile a large piece of legacy code. GCC
3.3 compiles it without complaining, but GCC 4.2.3 (the default in
Debian) refuses it and signals "several array has incomplete element
type" errors.

I know that since 4.0 or so, GCC is less forgiving and does not accept
any arrays of incomplete type (see http://gcc.gnu.org/ml/gcc/2005-02/msg00053.html).
However, I cannot see where the array types are incomplete here:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char [][], const int, const int,
const int, const int y);

/* From the source: ERROR: Array type has incomplete element type */
void grphcs_enhnc_ou tsquare(unsigne d char outsquare[][], const int w,
const int h, const int x, const int y)
{ /* ... */ }

/* From another header */
extern void bz_comp(int, int [], int [], int [], int *, int [][], int
*[]);

/* From the corresponding source: ERROR: Array type has incomplete
element type */
void bz_comp(
int npoints,
int xcol[ MAX_BOZORTH_MIN UTIAE ],
int ycol[ MAX_BOZORTH_MIN UTIAE ],
int thetacol[ MAX_BOZORTH_MIN UTIAE ],

int * ncomparisons,
int cols[][ COLS_SIZE_2 ],
int * colptrs[]
)
{ /* ... */ }
Can anyone shed some light?

Thanks in advance

extern void
bz_comp(int, int [], int [], int [], int *,
int [][COLS_SIZE_2], int *[]);

--
pete

[arcadio]

On 23 jun, 17:59, Lew Pitcher <lpitc...@teksa vvy.comwrote:

In comp.lang.c, arcadio wrote:

Hi everyone,

I'm currently struggling to compile a large piece of legacy code. GCC
3.3 compiles it without complaining, but GCC 4.2.3 (the default in
Debian) refuses it and signals "several array has incomplete element
type" errors.

[snip]

/* From the corresponding source: ERROR: Array type has incomplete
element type */
void bz_comp(
int npoints,
int xcol[ * * MAX_BOZORTH_MIN UTIAE ],
int ycol[ * * MAX_BOZORTH_MIN UTIAE ],
int thetacol[ MAX_BOZORTH_MIN UTIAE ],

int * ncomparisons,
int cols[][ COLS_SIZE_2 ],

How many cols elements are in this array? How can the compiler determine
that number?

int * colptrs[]
)
{ /* ... */ }

Can anyone shed some light?

Thanks in advance

- Arcadio

--
Lew Pitcher

Master Codewright & JOAT-in-training | Registered Linux User #112576http://pitcher.digital freehold.ca/* | GPG public key available by request
---------- * * *Slackware - Because I know what I'm doing. * * * * *------

The error is not there, it's:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char **, const int, const int,
<-- transform into pointers
const int, const int y);

/* From the source: ERROR: Array type has incomplete element type */
void grphcs_enhnc_ou tsquare(unsigne d char **outsquare, const int w,
<-- transform into pointers
const int h, const int x, const int y)
{ /* ... */ }

/* From another header */
extern void bz_comp(int, int [], int [], int [], int *, int []
[COLS_SIZE_2], int <- constant needed
*[]);

/* From the corresponding source: ERROR: Array type has incomplete
element type */
void bz_comp(
int npoints,
int xcol[ MAX_BOZORTH_MIN UTIAE ],
int ycol[ MAX_BOZORTH_MIN UTIAE ],
int thetacol[ MAX_BOZORTH_MIN UTIAE ],

int * ncomparisons,
int cols[][ COLS_SIZE_2 ],
int * colptrs[]
)
{ /* ... */ }

[Kenny McCormack]

In article <6d************ *************** ***@bt.com>,
Richard Heathfield <rj*@see.sig.in validwrote:

>arcadio said:

<snip>

>However, I cannot see
where the array types are incomplete here:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char [][]

^^^^
Right here.

Regarding your subject line, "Array has incomplete element type. GCC bug?",
it is generally wisest in the first instance[1] to assume that the bug is
in your code unless you can demonstrate from the Standard that your code
is correct.

While I agree with the sentiment here (including the footnote(s)), the
salient fact here is that OP says it worked (compiled) with the earlier
versions of GCC. Now, assuming he isn't mistaken about that, the fact
is that you can standards-jockey it all you want, it ain't gonna mean
much. Believe me, if TPTB (the ones who are paying the bills) know that
it worked before and it doesn't work now, then, for all practical
purposes, it is a bug (in the new version) - and no amount of
standards-jockeying is going to change that fact.

Or, to put it a little bit more charitably, OP's post can (and should)
be interpreted as: It worked before; it doesn't work now; is there a
workaround?

[Harald van =?UTF-8?b?RMSzaw==?=]

On Mon, 23 Jun 2008 19:17:17 +0000, Kenny McCormack wrote:

In article <6d************ *************** ***@bt.com>, Richard Heathfield
<rj*@see.sig.in validwrote:

>>arcadio said:

<snip>

>>However, I cannot see
where the array types are incomplete here:

/* From the header */
void grphcs_enhnc_ou tsquare(unsigne d char [][]

^^^^
Right here.

[...]
Or, to put it a little bit more charitably, OP's post can (and should)
be interpreted as: It worked before; it doesn't work now; is there a
workaround?

Sure: declare a pointer to an array of unsigned char of unknown length.

void grphcs_enhnc_ou tsquare(unsigne d char (*)[], ...);
void grphcs_enhnc_ou tsquare(unsigne d char (*outsquare)[], ...) {
...
}

This is what the declaration meant with those older versions of GCC, and
what it would mean in standard C if it weren't specifically disallowed,
anyway.

I'd be surprised to find a sensible use for this type of declaration,
though. It's valid and compiles, but all the other problems of
unsigned char [][] remain, so it would still be good to find a better type
to use.

[Walter Roberson]

In article <6c************ *@mid.individua l.net>,
bl****@myrealbo x.com <bl****@myrealb ox.comwrote:

>In article <86************ *************** *******@k37g200 0hsf.googlegrou ps.com>,
arcadio <ar************ ****@gmail.comw rote:

>Thanks, I was quite obfuscated

>Point of English usage: Can one speak of a person being
obfuscated,

Yes. OED has a secondary meaning that makes it clear that it can
apply to a person:

2. Of a person or his or her faculties: confused, bewildered;
amazed, flabbergasted (obs.); (U.S. slang) spec. befuddled with
alcohol, intoxicated (now rare).

There are a few examples given, such as

1860 `G. ELIOT' Mill on Floss I. I. vii. 125 As for uncle Pullet, he
could hardly have been more thoroughly obfuscated if Mr Tulliver had
said that he was going to send Tom to the Lord Chancellor.
--
"[i]t lacks context, and may or may not make sense."
-- Walter J. Phillips

[blmblm]

In article <g3**********@c anopus.cc.umani toba.ca>,
Walter Roberson <ro******@ibd.n rc-cnrc.gc.cawrote :

In article <6c************ *@mid.individua l.net>,
bl****@myrealbo x.com <bl****@myrealb ox.comwrote:

In article <86************ *************** *******@k37g200 0hsf.googlegrou ps.com>,
arcadio <ar************ ****@gmail.comw rote:

Thanks, I was quite obfuscated

Point of English usage: Can one speak of a person being
obfuscated,

Yes. OED has a secondary meaning that makes it clear that it can
apply to a person:

2. Of a person or his or her faculties: confused, bewildered;
amazed, flabbergasted (obs.); (U.S. slang) spec. befuddled with
alcohol, intoxicated (now rare).

There are a few examples given, such as

1860 `G. ELIOT' Mill on Floss I. I. vii. 125 As for uncle Pullet, he
could hardly have been more thoroughly obfuscated if Mr Tulliver had
said that he was going to send Tom to the Lord Chancellor.
--
"[i]t lacks context, and may or may not make sense."
-- Walter J. Phillips

Huh! The entry in the online Merriam-Webster

http://www.merriam-webster.com/dictionary/obfuscated

doesn't seem to give this meaning. But okay, I've learned
something!

(If it matters, my post was meant to be possibly-useful information
for someone for whom English might not be a first language. But
maybe he(?) knows it better than I do. Sort of a :-). )

--
B. L. Massingill
ObDisclaimer: I don't speak for my employers; they return the favor.

[Richard Heathfield]

bl****@myrealbo x.com said:

In article <g3**********@c anopus.cc.umani toba.ca>,
Walter Roberson <ro******@ibd.n rc-cnrc.gc.cawrote :

>In article <6c************ *@mid.individua l.net>,
bl****@myrealbo x.com <bl****@myrealb ox.comwrote:

<snip>

>Point of English usage: Can one speak of a person being
obfuscated,

Yes. OED has a secondary meaning that makes it clear that it can
apply to a person:

[...]

>
Huh! The entry in the online Merriam-Webster

http://www.merriam-webster.com/dictionary/obfuscated

doesn't seem to give this meaning. But okay, I've learned
something!

Yes, you've learned that you get the dictionary you pay for. :-)

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999