Properly implement the C interfaces in progeo

[ojgarciab]

When compiling code there is some warnings that have to be avoided:

Scanning dependencies of target progeo
[ 29%] Building C object src/stable/libs/progeo/CMakeFiles/progeo.dir/progeo.c.o
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:581:6: warning: conflicting types for ‘update_camera_matrix’ [enabled by default]
 void update_camera_matrix(TPinHoleCamera *camera)
      ^
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:345:2: note: previous implicit declaration of ‘update_camera_matrix’ was here
  update_camera_matrix(&camera);
  ^
Linking C static library libprogeo.a
[ 29%] Built target progeo
Scanning dependencies of target progeoshare
[ 29%] Building C object src/stable/libs/progeo/CMakeFiles/progeoshare.dir/progeo.c.o
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:581:6: warning: conflicting types for ‘update_camera_matrix’ [enabled by default]
 void update_camera_matrix(TPinHoleCamera *camera)
      ^
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:345:2: note: previous implicit declaration of ‘update_camera_matrix’ was here
  update_camera_matrix(&camera);
  ^
Linking C shared library libprogeo.so

This problem is due to lack of definition of the functions in C compiler at the header file:

#ifdef __cplusplus
extern "C" {
    TPinHoleCamera xmlReader(TPinHoleCamera* camera, const char *filename);
    void xmlWriter(TPinHoleCamera camera, const char *filename);
    void update_camera_matrix(TPinHoleCamera *camera);
    void reverse_update_camera_matrix(TPinHoleCamera *camera);
    void update_stereocamera_matrix(TPinHoleStereocamera *stereo);
    int project(HPoint3D in, HPoint2D *out, TPinHoleCamera camera);
    int backproject(HPoint3D *out, HPoint2D in, TPinHoleCamera camera);
    int displayline(HPoint2D p1, HPoint2D p2, HPoint2D *a, HPoint2D *b, TPinHoleCamera camera);
    void display_camerainfo(TPinHoleCamera camera);
}
#endif

It could be fixed creating a "else" case:

#ifdef __cplusplus
extern "C" {
    TPinHoleCamera xmlReader(TPinHoleCamera* camera, const char *filename);
    void xmlWriter(TPinHoleCamera camera, const char *filename);
    void update_camera_matrix(TPinHoleCamera *camera);
    void reverse_update_camera_matrix(TPinHoleCamera *camera);
    void update_stereocamera_matrix(TPinHoleStereocamera *stereo);
    int project(HPoint3D in, HPoint2D *out, TPinHoleCamera camera);
    int backproject(HPoint3D *out, HPoint2D in, TPinHoleCamera camera);
    int displayline(HPoint2D p1, HPoint2D p2, HPoint2D *a, HPoint2D *b, TPinHoleCamera camera);
    void display_camerainfo(TPinHoleCamera camera);
}
#else
TPinHoleCamera xmlReader(TPinHoleCamera* camera, const char *filename);
void xmlWriter(TPinHoleCamera camera, const char *filename);
void update_camera_matrix(TPinHoleCamera *camera);
void reverse_update_camera_matrix(TPinHoleCamera *camera);
void update_stereocamera_matrix(TPinHoleStereocamera *stereo);
int project(HPoint3D in, HPoint2D *out, TPinHoleCamera camera);
int backproject(HPoint3D *out, HPoint2D in, TPinHoleCamera camera);
int displayline(HPoint2D p1, HPoint2D p2, HPoint2D *a, HPoint2D *b, TPinHoleCamera camera);
void display_camerainfo(TPinHoleCamera camera);
#endif

But this change will fire a critical compile error:

[ 29%] Built target JderobotInterfaces
Scanning dependencies of target progeo
[ 29%] Building C object src/stable/libs/progeo/CMakeFiles/progeo.dir/progeo.c.o
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c: In function ‘reverse_update_camera_matrix’:
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:536:2: error: incompatible type for argument 3 of ‘backproject’
  backproject(&out, in, camera);
  ^
In file included from /home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:23:0:
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.h:105:5: note: expected ‘TPinHoleCamera’ but argument is of type ‘struct TPinHoleCamera *’
 int backproject(HPoint3D *out, HPoint2D in, TPinHoleCamera camera);
     ^
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:561:2: error: incompatible type for argument 3 of ‘backproject’
  backproject(&p3, p2_rt_complete, camera);
  ^
In file included from /home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.c:23:0:
/home/redstar/Documentos/jderobot/temp/JdeRobot/src/stable/libs/progeo/progeo.h:105:5: note: expected ‘TPinHoleCamera’ but argument is of type ‘struct TPinHoleCamera *’
 int backproject(HPoint3D *out, HPoint2D in, TPinHoleCamera camera);
     ^
make[2]: *** [src/stable/libs/progeo/CMakeFiles/progeo.dir/progeo.c.o] Error 1
make[1]: *** [src/stable/libs/progeo/CMakeFiles/progeo.dir/all] Error 2
make: *** [all] Error 2

So we need to change proceo.c too:

@@ -533,7 +533,7 @@
    in.y = 0;
    in.h = 0;

-   backproject(&out, in, camera);
+   backproject(&out, in, *camera);

    camera->foa.X = out.X;
    camera->foa.Y = out.Y;
@@ -558,7 +558,7 @@
    p2_rt_complete.y = 1;
    p2_rt_complete.h = 0;

-   backproject(&p3, p2_rt_complete, camera);
+   backproject(&p3, p2_rt_complete, *camera);

    TPinHoleCamera cameraAux; 
    cameraAux = *camera;

But I don't want to upload this fix because I don't use progeo.

Please, could someone that use progeo test my patch?

Thanks!

[varhub]

Hello @ojgarciab, I checked it and you was right, even in dangerous consideration of change:
_any code that uses progeo with this compiler bug is using an incorrect implicit API_
discussion at #18