diff --git a/tools/grib_check_gaussian_grid.c b/tools/grib_check_gaussian_grid.c
index 128fc257c..50a79f352 100644
--- a/tools/grib_check_gaussian_grid.c
+++ b/tools/grib_check_gaussian_grid.c
@@ -28,7 +28,7 @@ int exit_on_error = 1; /* By default exit if any check fails */
 int verbose       = 0; /* By default quiet unless errors */
 int error_count   = 0;
 
-int DBL_EQUAL(double d1, double d2, double tolerance)
+static int DBL_EQUAL(double d1, double d2, double tolerance)
 {
     return fabs(d1 - d2) <= tolerance;
 }
@@ -46,7 +46,7 @@ static void usage(const char* prog)
 }
 
 /* Print an error message and optionally die */
-void error(const char* filename, int msg_num, const char* fmt, ...)
+static void error(const char* filename, int msg_num, const char* fmt, ...)
 {
     char buf[1024] = {0,};
     va_list list;
@@ -64,7 +64,7 @@ void error(const char* filename, int msg_num, const char* fmt, ...)
     }
 }
 
-double get_precision(long edition)
+static double get_precision(long edition)
 {
     if (edition == 1)
         return 1.0 / 1000.0; /* milli degrees */
@@ -74,7 +74,7 @@ double get_precision(long edition)
     return 0.0;
 }
 
-int process_file(const char* filename)
+static int process_file(const char* filename)
 {
     int err = 0, msg_num = 0;
     grib_handle* h = NULL;
diff --git a/tools/grib_to_json.c b/tools/grib_to_json.c
index 62f4e548e..187573a7e 100644
--- a/tools/grib_to_json.c
+++ b/tools/grib_to_json.c
@@ -12,7 +12,7 @@
 
 typedef void (*getproc)(FILE*, grib_handle*, const char*, const char*);
 
-void get_long(FILE* f, grib_handle* h, const char* name, const char* arg)
+static void get_long(FILE* f, grib_handle* h, const char* name, const char* arg)
 {
     const char* key = arg ? arg : name;
     long value;
@@ -20,7 +20,7 @@ void get_long(FILE* f, grib_handle* h, const char* name, const char* arg)
     fprintf(f, "\"%s\":%ld\n", name, value);
 }
 
-void get_param(FILE* f, grib_handle* h, const char* name, const char* arg)
+static void get_param(FILE* f, grib_handle* h, const char* name, const char* arg)
 {
     const char* key = "indicatorOfParameter";
     long value;
@@ -28,7 +28,7 @@ void get_param(FILE* f, grib_handle* h, const char* name, const char* arg)
     fprintf(f, "\"%s\":%ld\n", name, value - 131 + 2);
 }
 
-void get_iso_ref_date(FILE* f, grib_handle* h, const char* name, const char* arg)
+static void get_iso_ref_date(FILE* f, grib_handle* h, const char* name, const char* arg)
 {
     long year;
     long month;