Fix '-Wunused-parameter' compiler warnings (#2770)

The absolute majority of the "-Wunused-parameter" compiler warnings are addressed by adding
__attribute__((unused)) with the macro 'UNUSED'.

.github/workflows/gcc.yml

@@ -56,8 +56,8 @@ jobs:
         env:
           # TODO: -pedantic-errors here won't go through ./configure (with GNU C)
           CFLAGS: -std=${{ matrix.c }} -fPIC -Wall -Wextra
-            -Wno-error=implicit-fallthrough -Wno-error=unused-parameter
+            -Wno-error=implicit-fallthrough
           # TODO: -pedantic-errors here won't compile
           CXXFLAGS: -std=${{ matrix.cpp }} -fPIC -Wall -Wextra
-            -Wno-error=implicit-fallthrough -Wno-error=unused-parameter
+            -Wno-error=implicit-fallthrough
         run: .github/workflows/build_ubuntu-22.04.sh $HOME/install -Werror

.github/workflows/macos_install.sh

@@ -66,8 +66,8 @@ CONFIGURE_FLAGS="\
   --with-readline-libs=${CONDA_PREFIX}/lib
 "
 
-export CFLAGS="-O2 -pipe -arch ${CONDA_ARCH} -DGL_SILENCE_DEPRECATION -Wall -Wextra -Wno-error=unused-parameter"
-export CXXFLAGS="-O2 -pipe -stdlib=libc++ -arch ${CONDA_ARCH} -Wall -Wextra -Wno-error=unused-parameter"
+export CFLAGS="-O2 -pipe -arch ${CONDA_ARCH} -DGL_SILENCE_DEPRECATION -Wall -Wextra"
+export CXXFLAGS="-O2 -pipe -stdlib=libc++ -arch ${CONDA_ARCH} -Wall -Wextra"
 
 ./configure $CONFIGURE_FLAGS
 

db/drivers/dbf/dbfexe.c

@@ -343,7 +343,8 @@ void get_col_def(SQLPSTMT *st, int col, int *type, int *width, int *decimals)
     }
 }
 
-void eval_val(int tab, int row, int col, SQLPVALUE *inval, SQLPVALUE *val)
+void eval_val(int tab, int row, int col UNUSED, SQLPVALUE *inval,
+              SQLPVALUE *val)
 {
 
     double retval;

db/drivers/dbf/driver.c

@@ -18,7 +18,7 @@
 #include "globals.h"
 #include "proto.h"
 
-int db__driver_init(int argc, char *argv[])
+int db__driver_init(int argc UNUSED, char *argv[] UNUSED)
 {
     init_error();
     return DB_OK;

db/drivers/dbf/listtab.c

@@ -18,7 +18,7 @@
 #include "globals.h"
 #include "proto.h"
 
-int db__driver_list_tables(dbString **tlist, int *tcount, int system)
+int db__driver_list_tables(dbString **tlist, int *tcount, int system UNUSED)
 {
     dbString *list;
     int i;

db/drivers/ogr/driver.c

@@ -25,7 +25,7 @@
 
    \return DB_OK on success
  */
-int db__driver_init(int argc, char *argv[])
+int db__driver_init(int argc UNUSED, char *argv[] UNUSED)
 {
     init_error();
     return DB_OK;

db/drivers/ogr/listtab.c

@@ -30,7 +30,7 @@
    \return DB_OK on success
    \return DB_FAILED on failure
  */
-int db__driver_list_tables(dbString **tlist, int *tcount, int system)
+int db__driver_list_tables(dbString **tlist, int *tcount, int system UNUSED)
 {
     int i, nlayers;
     dbString *list;

db/drivers/postgres/db.c

@@ -19,7 +19,7 @@
 #include "globals.h"
 #include "proto.h"
 
-static void notice_processor(void *arg, const char *message)
+static void notice_processor(void *arg UNUSED, const char *message)
 {
     /* print notice messages only on verbose level */
     if (G_verbose() > G_verbose_std()) {

db/drivers/postgres/driver.c

@@ -2,7 +2,7 @@
 #include "globals.h"
 #include "proto.h"
 
-int db__driver_init(int argc, char *argv[])
+int db__driver_init(int argc UNUSED, char *argv[] UNUSED)
 {
     init_error();
     return DB_OK;

db/drivers/sqlite/driver.c

@@ -15,7 +15,7 @@
 #include "globals.h"
 #include "proto.h"
 
-int db__driver_init(int argc, char *argv[])
+int db__driver_init(int argc UNUSED, char *argv[] UNUSED)
 {
     init_error();
 

db/drivers/sqlite/main.c

@@ -28,7 +28,7 @@ int main(int argc, char *argv[])
     exit(db_driver(argc, argv));
 }
 
-int sqlite_busy_callback(void *arg, int n_calls)
+int sqlite_busy_callback(void *arg UNUSED, int n_calls)
 {
     static time_t start_time = 0;
     time_t curr_time;

display/d.path/select.c

@@ -11,7 +11,7 @@
 
 #define WDTH 5
 
-int display(struct Map_info *Map, struct line_pnts *Points,
+int display(struct Map_info *Map UNUSED, struct line_pnts *Points,
             const struct color_rgb *color, int first, int last, int be_bold)
 {
     int from, to;

display/d.rhumbline/plot.c

@@ -5,7 +5,7 @@
 #include "local_proto.h"
 
 void plot(double lon1, double lat1, double lon2, double lat2, int line_color,
-          int text_color)
+          int text_color UNUSED)
 {
     int nsteps = 1000;
     int i;

display/d.vect.thematic/area.c

@@ -16,7 +16,7 @@
 int dareatheme(struct Map_info *Map, struct cat_list *Clist,
                dbCatValArray *cvarr, double *breaks, int nbreaks,
                const struct color_rgb *colors, const struct color_rgb *bcolor,
-               int chcat, struct Cell_head *window, int default_width)
+               int chcat, struct Cell_head *window, int default_width UNUSED)
 {
 
     int num, area, isle, n_isles, n_points;

display/d.vect.thematic/display.c

@@ -139,7 +139,7 @@ int display_lines(struct Map_info *Map, struct cat_list *Clist, int chcat,
 }
 
 int draw_line(int ltype, int line, const struct line_pnts *Points,
-              const struct line_cats *Cats, int chcat, double size,
+              const struct line_cats *Cats, int chcat, double size UNUSED,
               int default_width, const struct cat_list *Clist, SYMBOL *Symb,
               RGBA_Color *primary_color, int *n_points, int *n_lines,
               int *n_centroids, int *n_boundaries, int *n_faces,

display/d.vect.thematic/plot1.c

@@ -38,9 +38,10 @@ struct rgb_color palette[16] = {
 /* *************************************************************** */
 /* *************************************************************** */
 /* *************************************************************** */
-int plot1(struct Map_info *Map, int type, int area, struct cat_list *Clist,
-          const struct color_rgb *color, const struct color_rgb *fcolor,
-          int chcat, SYMBOL *Symb, int size, int id_flag, int table_colors_flag,
+int plot1(struct Map_info *Map, int type, int area UNUSED,
+          struct cat_list *Clist, const struct color_rgb *color,
+          const struct color_rgb *fcolor, int chcat, SYMBOL *Symb,
+          int size UNUSED, int id_flag, int table_colors_flag,
           int cats_color_flag, char *rgb_column, int default_width,
           char *width_column, double width_scale)
 {

general/g.findfile/element.c

@@ -9,7 +9,9 @@ void list_elements(void)
     M_show_elements();
 }
 
+#if 0
 int check_element(const char *element)
 {
     return M_read_list(FALSE, NULL);
 }
+#endif

general/g.findfile/local_proto.h

@@ -1,3 +1,3 @@
 /* element.c */
 void list_elements(void);
-int check_element(const char *);
+/* int check_element(const char *); */

imagery/i.eb.netrad/r_net.c

@@ -5,8 +5,9 @@
 
 #define PI M_PI
 
-double r_net(double bbalb, double ndvi, double tempk, double dtair, double e0,
-             double tsw, double doy, double utc, double sunzangle)
+double r_net(double bbalb, double ndvi UNUSED, double tempk, double dtair,
+             double e0, double tsw, double doy, double utc UNUSED,
+             double sunzangle)
 {
 
     /* Tsw =  atmospheric transmissivity single-way (~0.7 -) */

imagery/i.evapo.mh/mh_original.c

@@ -1,9 +1,11 @@
 #include <stdio.h>
 #include <math.h>
 #include <stdlib.h>
+#include <grass/gis.h>
 
 /*Hargreaves et al, 1985. */
-double mh_original(double ra, double tavg, double tmax, double tmin, double p)
+double mh_original(double ra, double tavg, double tmax, double tmin,
+                   double p UNUSED)
 {
     double td, result;
 

imagery/i.evapo.pm/functions.c

@@ -97,8 +97,8 @@ DCELL calc_ETp(DCELL T, DCELL Z, DCELL u2, DCELL Rn, int night, DCELL Rh,
     return ETp;
 }
 
-DCELL calc_openwaterETp(DCELL T, DCELL Z, DCELL u2, DCELL Rn, int day, DCELL Rh,
-                        DCELL hc)
+DCELL calc_openwaterETp(DCELL T, DCELL Z, DCELL u2, DCELL Rn, int day UNUSED,
+                        DCELL Rh, DCELL hc UNUSED)
 {
     DCELL ea, delta, gamma, lambda;
     DCELL P, ed, ETaero, ETp;

imagery/i.gensig/alloc.c

@@ -24,14 +24,14 @@ double **matrix(int nrl, int nrh, int ncl, int nch)
     return m;
 }
 
-int free_vector(double *v, int nl, int nh)
+int free_vector(double *v, int nl, int nh UNUSED)
 {
     G_free((char *)(v + nl));
 
     return 0;
 }
 
-int free_matrix(double **m, int nrl, int nrh, int ncl, int nch)
+int free_matrix(double **m, int nrl, int nrh, int ncl, int nch UNUSED)
 {
     int i;
 

imagery/i.ortho.photo/lib/cam_info.c

@@ -60,8 +60,8 @@ int I_read_cam_info(FILE *fd, struct Ortho_Camera_File_Ref *cam_info)
     return 1;
 }
 
-int I_new_fid_point(struct Ortho_Camera_File_Ref *cam_info, char fid_id[30],
-                    double Xf, double Yf)
+int I_new_fid_point(struct Ortho_Camera_File_Ref *cam_info UNUSED,
+                    char fid_id[30] UNUSED, double Xf UNUSED, double Yf UNUSED)
 {
     return 0;
 }

imagery/i.ortho.photo/lib/orthoref.c

@@ -611,8 +611,8 @@ int I_compute_ortho_equations(struct Ortho_Control_Points *cpz,
 /* given ground coordinates (e1,n1,z1) and the solution from above */
 /* compute the photo coordinate (e2,n2) position */
 int I_ortho_ref(double e1, double n1, double z1, double *e2, double *n2,
-                double *z2, struct Ortho_Camera_File_Ref *cam_info, double XC,
-                double YC, double ZC, MATRIX M)
+                double *z2 UNUSED, struct Ortho_Camera_File_Ref *cam_info,
+                double XC, double YC, double ZC, MATRIX M)
 {
     MATRIX UVW, XYZ;
     double U, V, W;
@@ -683,8 +683,9 @@ int I_ortho_ref(double e1, double n1, double z1, double *e2, double *n2,
 /* and the solution from I_compute_ortho_equation */
 /* compute ground position (e2,n2) */
 int I_inverse_ortho_ref(double e1, double n1, double z1, double *e2, double *n2,
-                        double *z2, struct Ortho_Camera_File_Ref *cam_info,
-                        double XC, double YC, double ZC, MATRIX M)
+                        double *z2 UNUSED,
+                        struct Ortho_Camera_File_Ref *cam_info, double XC,
+                        double YC, double ZC, MATRIX M)
 {
     MATRIX UVW, XYZ;
     double lam, mu, nu;

imagery/i.segment/watershed.c

@@ -14,7 +14,7 @@
 #include <grass/rbtree.h>  /* Red Black Tree library functions */
 #include "iseg.h"
 
-int watershed(struct globals *globals)
+int watershed(struct globals *globals UNUSED)
 {
     G_fatal_error(_("Watershed is not yet implemented"));
 

include/grass/defs/gis.h

@@ -690,8 +690,8 @@ double G_transverse_radius_of_curvature(double, double, double);
 double G_radius_of_conformal_tangent_sphere(double, double, double);
 
 /* rd_cellhd.c */
-void G__read_Cell_head(FILE *, struct Cell_head *, int);
-void G__read_Cell_head_array(char **, struct Cell_head *, int);
+void G__read_Cell_head(FILE *, struct Cell_head *);
+void G__read_Cell_head_array(char **, struct Cell_head *);
 
 /* remove.c */
 int G_remove(const char *, const char *);
@@ -818,7 +818,7 @@ int G_set_verbose(int);
 /* view.c */
 void G_3dview_warning(int);
 int G_get_3dview_defaults(struct G_3dview *, struct Cell_head *);
-int G_put_3dview(const char *, const char *, const struct G_3dview *,
+int G_put_3dview(const char *, const struct G_3dview *,
                  const struct Cell_head *);
 int G_get_3dview(const char *, const char *, struct G_3dview *);
 

include/grass/gis.h

@@ -36,8 +36,18 @@
 #define __attribute__(x)
 #endif
 
-static const char *GRASS_copyright __attribute__((unused)) =
-    "GRASS GNU GPL licensed Software";
+/*!
+    \def UNUSED
+    \brief A macro for an attribute, if attached to a variable,
+           indicating that the variable is not used
+*/
+#if (defined(__GNUC__) || defined(__APPLE__)) && !defined(_MSC_VER)
+#define UNUSED __attribute__((unused))
+#else
+#define UNUSED
+#endif
+
+static const char *GRASS_copyright UNUSED = "GRASS GNU GPL licensed Software";
 
 /* GRASS version, GRASS date, git short hash of last change in GRASS headers
  * (and anything else in include)

include/grass/iostream/embuffer.h

@@ -137,7 +137,7 @@ class merge_key {
     {
         return (x.k == y.k);
     }
-    friend merge_key operator+(const merge_key &x, const merge_key &y)
+    friend merge_key operator+(const merge_key &x, const merge_key &y UNUSED)
     {
         assert(0);
         return x;
@@ -533,7 +533,7 @@ em_buffer<T, Key>::~em_buffer()
 // memory (by a previous get_stream call, for instance) in order to
 // find its length
 template <class T, class Key>
-void em_buffer<T, Key>::check_name(unsigned int i)
+void em_buffer<T, Key>::check_name(unsigned int i UNUSED)
 {
 
 #ifdef EMBUF_CHECK_NAME

include/grass/iostream/empq.h

@@ -161,7 +161,7 @@ class em_pqueue {
 
     // create an em_pqueue capable to store <= N elements
     em_pqueue();
-    em_pqueue(long N) { em_pqueue(); }; // N not used
+    em_pqueue(long N UNUSED) { em_pqueue(); }; // N not used
 
 #ifdef SAVE_MEMORY
     // create an empq, initialize its pq with im and insert amis in

include/grass/iostream/empq_adaptive.h

@@ -57,7 +57,7 @@ class EMPQueueAdaptive {
 public:
     /* start in INMEM regim by allocating im of size precisely twice the
        size of the (pqueue within) the em_pqueue; */
-    EMPQueueAdaptive(long N) : EMPQueueAdaptive(){};
+    EMPQueueAdaptive(long N UNUSED) : EMPQueueAdaptive(){};
     EMPQueueAdaptive();
     EMPQueueAdaptive(size_t inMem);
     ~EMPQueueAdaptive();

lib/calc/calc.c

@@ -12,7 +12,7 @@ int columns;
 
 /****************************************************************************/
 
-static void handle_fpe(int n)
+static void handle_fpe(int n UNUSED)
 {
     floating_point_exception = 1;
     floating_point_exception_occurred = 1;

lib/calc/xif.c

@@ -9,7 +9,7 @@
  if(a,b,c,d)  d,c,b  b if a is positive, c if a is zero, d if a is negative
 ********************************************************************/
 
-static int f_if_i(int argc, const int *argt, void **args)
+static int f_if_i(int argc, const int *argt UNUSED, void **args)
 {
     CELL *res = args[0];
     DCELL *arg1 = args[1];
@@ -89,7 +89,7 @@ static int f_if_i(int argc, const int *argt, void **args)
     return 0;
 }
 
-static int f_if_f(int argc, const int *argt, void **args)
+static int f_if_f(int argc, const int *argt UNUSED, void **args)
 {
     FCELL *res = args[0];
     DCELL *arg1 = args[1];
@@ -164,7 +164,7 @@ static int f_if_f(int argc, const int *argt, void **args)
     return 0;
 }
 
-static int f_if_d(int argc, const int *argt, void **args)
+static int f_if_d(int argc, const int *argt UNUSED, void **args)
 {
     DCELL *res = args[0];
     DCELL *arg1 = args[1];

lib/cdhc/test.c

@@ -4,7 +4,7 @@
 #include <grass/cdhc.h>
 #include "local_proto.h"
 
-int main(int argc, char **argv)
+int main(void)
 {
     double z[1000];
     double *w;