+ res += fprintf (out, "-%d", end_col);
+ }
+
+ return res;
+}
+
+
+/* Persistant data used by location_caret to avoid reopening and rereading the
+ same file all over for each error. */
+struct caret_info
+{
+ FILE *source;
+ size_t line;
+ size_t offset;
+};
+
+static struct caret_info caret_info = { NULL, 1, 0 };
+
+void
+cleanup_caret ()
+{
+ if (caret_info.source)
+ fclose (caret_info.source);
+ caret_info.source = NULL;
+ caret_info.line = 1;
+ caret_info.offset = 0;
+}
+
+void
+location_caret (location loc, FILE *out)
+{
+ /* FIXME: find a way to support multifile locations, and only open once each
+ file. That would make the procedure future-proof. */
+ if (! (caret_info.source
+ || (caret_info.source = fopen (loc.start.file, "r")))
+ || loc.start.column == -1 || loc.start.line == -1)
+ return;
+
+ /* If the line we want to quote is seekable (the same line as the previous
+ location), just seek it. If it was a previous line, we lost track of it,
+ so return to the start of file. */
+ if (caret_info.line <= loc.start.line)
+ fseek (caret_info.source, caret_info.offset, SEEK_SET);
+ else
+ {
+ caret_info.line = 1;
+ caret_info.offset = 0;
+ fseek (caret_info.source, caret_info.offset, SEEK_SET);