[Proj] PROJ 4.8.0, projects.h and projPJ struct

[Frank Warmerdam]

Eric,

This seems reasonable.  Don't hesitate to file a ticket ideally with a patch.

Best regards,
Frank

On Wed, Apr 11, 2012 at 8:25 AM, Eric Miller <EMiller at dfg.ca.gov> wrote:
> I think that being able to interrogate the projection definition to know
> if it has an inverse is useful, so a function should be added to
> proj_api.h.
>
> Perhaps:
>
> int pj_has_inverse(projPJ);
>
> And in pj_utils.c
>
> /******************************************************************/
> /*                                 pj_has_inverse()
>            */
> /*
>                   */
> /*            Return TRUE if this coordinate system object has     */
> /*            and inverse projection method.
>  */
> /*****************************************************************/
> int pj_has_inverse( PJ *pj )
> {
>         return pj != NULL && pj->inv != NULL;
> }
>
> --
>
> Eric G. Miller
> Software Developer
> CA Dept. of Fish & Game
>
>
>>>> On 4/11/2012 at  3:30 AM, José Luis García Pallero
> <jgpallero at gmail.com>
> wrote:
>> Hello:
>>
>> As it is said in NEWS files from PROJ 4.8.0 now proj_api.h file
> should
>> be included in programs instead projects.h. I've tried to compile my
>> old code (that has no problems with 4.7.0) and I've obtained a
> warning
>> and an error.
>> In my code I have a declaration like
>>
>> projPJ proyec;
>>
>> and I use them later as
>>
>> proyec = pj_init_plus(param);
>>
>> and more later, in order to check if a projections has inverse step:
>>
>> if(proyec->inv==0)
>> {
>> ......
>> }
>>
>> If I compile the program using 4.8.0 version I obtain a warning and
> an
>> error:
>>
>> geocproj.c:202:14: warning: dereferencing *void ** pointer
> [enabled by
>> default]
>> geocproj.c:202:14: error: request for member *inv* in something
> not a
>> structure or union
>>
>> Looking proj_api.h file, in both versions 4.7.0 and 4.8.0 I can see
> the
>> block
>>
>> for 4.7.0
>>
>> #if !defined(PROJECTS_H)
>>     typedef struct { double u, v; } projUV;
>>     typedef void *projPJ;
>>     #define projXY projUV
>>     #define projLP projUV
>> #else
>>     typedef PJ *projPJ;
>> #   define projXY     XY
>> #   define projLP       LP
>> #endif
>>
>> for 4.8.0
>>
>> #if !defined(PROJECTS_H)
>>     typedef struct { double u, v; } projUV;
>>     typedef void *projPJ;
>>     #define projXY projUV
>>     #define projLP projUV
>>     typedef void *projCtx;
>> #else
>>     typedef PJ *projPJ;
>>     typedef projCtx_t *projCtx;
>> #   define projXY     XY
>> #   define projLP       LP
>> #endif
>>
>> Both are the same (except for the ctx context). In both if
> PROJECTS_H
>> is not defined (i.e. if projects.h was not included) the type projPJ
>> is defined as void* instead PJ*. PJ is defined in projects.h. But in
>> the include/ folder of 4.8.0 project.h was not copied, so it's
>> impossible to use it. So I can't use the 'inv' field and I suppone
> no
>> PJ struct at all as projPJ was defined as void*. Then which is the
>> correct way in order to use the new PROJ 4.8.0 version?
>>
>>
>>
>> On the other hand, suppose that 4.8.0 works well in my case only
>> including proj_api.h. Then my problem is that if I have not
> knowledge
>> about the version of PROJ in one computer, how can I proceed in
> order
>> to use the correct include depending versions.
>> First of all, can I use version 4.7.0 (for example) with only
>> #include<proj_api.h>? In my case the answer is NO because I obtain
> the
>> same warning and error that in 4.8.0. Then I try:
>>
>> #include<proj_api.h>
>> #if PJ_VERSION<480
>> #include<projects.h>
>> #endif
>>
>> PJ_VERSION is defined in proj_api.h. I check if version is older
> than
>> 4.8.0 and try to include then projects.h. But I obtain some errors:
>>
>> /usr/include/projects.h:139:33: error: conflicting types for
> *projUV*
>> /usr/include/proj_api.h:54:37: note: previous declaration of
> *projUV*
>> was here
>> geocproj.c: In function *ProjFwd*:
>> geocproj.c:120:9: error: incompatible type for argument 1 of
> *pj_fwd*
>> /usr/include/proj_api.h:66:8: note: expected *projUV* but
> argument is
>> of type *projUV*
>> geocproj.c: In function *ProjInv*:
>> geocproj.c:202:14: warning: dereferencing *void ** pointer
> [enabled by
>> default]
>> geocproj.c:202:14: error: request for member *inv* in something
> not a
>> structure or union
>> geocproj.c:223:9: error: incompatible type for argument 1 of
> *pj_inv*
>> /usr/include/proj_api.h:67:8: note: expected *projUV* but
> argument is
>> of type *projUV*
>>
>> We can see conflicting type errors due to definitions of projUV in
>> proj_api.h and projects.h.
>>
>> Opinions about?
>>
>> Cheers
>
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-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer