i18n problem

[John Coppens <john jcoppens com>]

Hello people.

Since a few weeks, I put a Smith Charting program on the 'net, and when a
few users wanted to translate, I added i18n support to the program.
Everything goes fine, except for a few strings... Could someone indicate
me where the problem is?

I declared:

typedef struct {
  char *hdr;
  int w;
} loaddef[] = {
  {N_("F (MHz)"), 60},
  {N_("Real"),    50},
  {N_("Imag"),    50}
};

And later in the program, I used:

    col = gtk_tree_view_column_new_with_attributes(
                _(loaddef[def].hdr),
                renderer, "text", def,
                NULL);

That seemed quite straightforward, but the title are not translated for
some reason.

Ideas?
John