+/* Reads a line from 'file' into 'ds', clearing anything initially in 'ds'.
+ * Deletes comments introduced by "#" and skips lines that contains only white
+ * space (after deleting comments).
+ *
+ * Returns 0 if successful, EOF if no non-blank line was found. */
+int
+ds_get_preprocessed_line(struct ds *ds, FILE *file)
+{
+ while (!ds_get_line(ds, file)) {
+ char *line = ds_cstr(ds);
+ char *comment;
+
+ /* Delete comments. */
+ comment = strchr(line, '#');
+ if (comment) {
+ *comment = '\0';
+ }
+
+ /* Return successfully unless the line is all spaces. */
+ if (line[strspn(line, " \t\n")] != '\0') {
+ return 0;
+ }
+ }
+ return EOF;
+}
+