diff --git a/src/functions.c b/src/functions.c
index eae2722bc..3140d1598 100644
--- a/src/functions.c
+++ b/src/functions.c
@@ -140,7 +140,7 @@ double grib_op_le_d(double a, double b)
     if (proc == a) {   \
         return "&" #a; \
     }
-const char* grib_binop_long_proc_name(grib_binop_long_proc proc)
+const char* grib_binop_long_proc_name(const grib_binop_long_proc proc)
 {
     if (!proc)
         return "NULL";
@@ -165,7 +165,7 @@ const char* grib_binop_long_proc_name(grib_binop_long_proc proc)
     return NULL;
 }
 
-const char* grib_binop_double_proc_name(grib_binop_double_proc proc)
+const char* grib_binop_double_proc_name(const grib_binop_double_proc proc)
 {
     if (!proc)
         return "NULL";
@@ -184,7 +184,7 @@ const char* grib_binop_double_proc_name(grib_binop_double_proc proc)
     return NULL;
 }
 
-const char* grib_unop_long_proc_name(grib_unop_long_proc proc)
+const char* grib_unop_long_proc_name(const grib_unop_long_proc proc)
 {
     if (!proc)
         return "NULL";
@@ -195,7 +195,7 @@ const char* grib_unop_long_proc_name(grib_unop_long_proc proc)
     return NULL;
 }
 
-const char* grib_unop_double_proc_name(grib_unop_double_proc proc)
+const char* grib_unop_double_proc_name(const grib_unop_double_proc proc)
 {
     if (!proc)
         return "NULL";
diff --git a/src/grib_api_prototypes.h b/src/grib_api_prototypes.h
index f9293b814..8e071dbf5 100644
--- a/src/grib_api_prototypes.h
+++ b/src/grib_api_prototypes.h
@@ -698,7 +698,7 @@ int grib_jasper_encode(grib_context* c, j2k_encode_helper* helper);
 
 /* grib_openjpeg_encoding.c */
 int grib_openjpeg_encode(grib_context* c, j2k_encode_helper* helper);
-int grib_openjpeg_decode(grib_context* c, unsigned char* buf, size_t* buflen, double* val, size_t* n_vals);
+int grib_openjpeg_decode(grib_context* c, unsigned char* buf, const size_t* buflen, double* val, const size_t* n_vals);
 
 /* action_class_set_missing.c */
 grib_action* grib_action_create_set_missing(grib_context* context, const char* name);
@@ -1535,10 +1535,10 @@ double grib_op_lt_d(double a, double b);
 double grib_op_gt_d(double a, double b);
 double grib_op_ge_d(double a, double b);
 double grib_op_le_d(double a, double b);
-const char* grib_binop_long_proc_name(grib_binop_long_proc proc);
-const char* grib_binop_double_proc_name(grib_binop_double_proc proc);
-const char* grib_unop_long_proc_name(grib_unop_long_proc proc);
-const char* grib_unop_double_proc_name(grib_unop_double_proc proc);
+const char* grib_binop_long_proc_name(const grib_binop_long_proc proc);
+const char* grib_binop_double_proc_name(const grib_binop_double_proc proc);
+const char* grib_unop_long_proc_name(const grib_unop_long_proc proc);
+const char* grib_unop_double_proc_name(const grib_unop_double_proc proc);
 
 /* codes_memfs.c */
 FILE* codes_fopen(const char* name, const char* mode);
diff --git a/src/grib_iterator_class_gaussian_reduced.c b/src/grib_iterator_class_gaussian_reduced.c
index 832b392d7..bebb3cc13 100644
--- a/src/grib_iterator_class_gaussian_reduced.c
+++ b/src/grib_iterator_class_gaussian_reduced.c
@@ -128,7 +128,7 @@ static size_t count_subarea_points(grib_handle* h, get_reduced_row_proc get_redu
 }
 
 /* Search for 'x' in the array 'xx' (the index of last element being 'n') and return index in 'j' */
-static void binary_search(double xx[], const unsigned long n, double x, long* j)
+static void binary_search(const double xx[], const unsigned long n, double x, long* j)
 {
     /*This routine works only on descending ordered arrays*/
 #define EPSILON 1e-3
@@ -164,8 +164,8 @@ static int iterate_reduced_gaussian_subarea_legacy(grib_iterator* iter, grib_han
     double d       = 0;
     long ilon_first, ilon_last, i;
     grib_iterator_gaussian_reduced* self = (grib_iterator_gaussian_reduced*)iter;
-    get_reduced_row_proc get_reduced_row = &grib_get_reduced_row;
-    get_reduced_row                      = &grib_get_reduced_row_legacy; /* legacy algorithm */
+    /*get_reduced_row_proc get_reduced_row = &grib_get_reduced_row;*/
+    get_reduced_row_proc get_reduced_row   = &grib_get_reduced_row_legacy; /* legacy algorithm */
 
     if (h->context->debug) {
         const size_t np = count_subarea_points(h, get_reduced_row, pl, plsize, lon_first, lon_last);
diff --git a/src/grib_openjpeg_encoding.c b/src/grib_openjpeg_encoding.c
index ecee220e9..eec69cd2a 100644
--- a/src/grib_openjpeg_encoding.c
+++ b/src/grib_openjpeg_encoding.c
@@ -133,7 +133,7 @@ cleanup:
     return err;
 }
 
-int grib_openjpeg_decode(grib_context* c, unsigned char* buf, size_t* buflen, double* val, size_t* n_vals)
+int grib_openjpeg_decode(grib_context* c, unsigned char* buf, size_t* buflen, double* val, const size_t* n_vals)
 {
     int err = GRIB_SUCCESS;
     int i;
@@ -448,7 +448,7 @@ cleanup:
     return err;
 }
 
-int grib_openjpeg_decode(grib_context* c, unsigned char* buf, size_t* buflen, double* val, size_t* n_vals)
+int grib_openjpeg_decode(grib_context* c, unsigned char* buf, const size_t* buflen, double* val, const size_t* n_vals)
 {
     int err = GRIB_SUCCESS;
     int i;
@@ -545,7 +545,7 @@ cleanup:
 
 #else /* No OpenJPEG */
 
-int grib_openjpeg_decode(grib_context* c, unsigned char* buf, size_t* buflen, double* val, size_t* n_vals)
+int grib_openjpeg_decode(grib_context* c, unsigned char* buf, const size_t* buflen, double* val, size_t* n_vals)
 {
     grib_context_log(c, GRIB_LOG_ERROR, "grib_openjpeg_encoding.c: OpenJPEG JPEG support not enabled.");
     return GRIB_FUNCTIONALITY_NOT_ENABLED;
diff --git a/src/grib_optimize_decimal_factor.c b/src/grib_optimize_decimal_factor.c
index 517a9e869..9f183d4a1 100644
--- a/src/grib_optimize_decimal_factor.c
+++ b/src/grib_optimize_decimal_factor.c
@@ -23,7 +23,7 @@ static double epsilon()
     return e;
 }
 
-static int range()
+static int vrange()
 {
     return (int)(log(DBL_MAX) / log(10)) - 1;
 }
@@ -71,7 +71,7 @@ int grib_optimize_decimal_factor(grib_accessor* a, const char* reference_value,
     int inumax, inutil;
     long jdec, ie;
     int irep;
-    int RANGE      = range();
+    int RANGE      = vrange();
     double EPSILON = epsilon();
     double pa      = pmax - pmin;