Be verbose when the YAML parameters are overwritten by a -P command-line argument.

examples/main.c

@@ -396,8 +396,12 @@ int main(int argc, char *argv[]) {
     parser_read_file(paramFileName, params);
 
     /* Handle any command-line overrides. */
-    if (nparams > 0)
+    if (nparams > 0) {
+      message(
+          "Overwriting values read from the YAML file with command-line "
+          "values.");
       for (int k = 0; k < nparams; k++) parser_set_param(params, cmdparams[k]);
+    }
 
     /* And dump the parameters as used. */
     // parser_print_params(&params);

src/parser.c

@@ -133,6 +133,8 @@ void parser_set_param(struct swift_params *params, const char *namevalue) {
   int updated = 0;
   for (int i = 0; i < params->paramCount; i++) {
     if (strcmp(name, params->data[i].name) == 0) {
+      message("Using the value '%s' instead of '%s' for the parameter '%s'",
+              value, params->data[i].value, params->data[i].name);
       strcpy(params->data[i].value, value);
       updated = 1;
     }