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Re: Printing to STDERR when %d is "Cannot access memory ..."
From: |
Keith David Bershatsky |
Subject: |
Re: Printing to STDERR when %d is "Cannot access memory ..." |
Date: |
Wed, 13 Jun 2018 12:34:14 -0700 |
Thank you, Eli, for taking a look at this thread. The suggestion by Davis to
deal with the STDERR message avoids the crash.
My STDERR printout (with the NULL font now being assigned a 0 value) is as
follows:
it->c (120021)
char (ð)
w->hscroll (0)
hscl (false)
it->hpos (5)
it->vpos (0)
it->current_x (55)
new_x (55)
font->space_width (0)
it->lnum_pixel_width (55)
it->lnum_width (3)
it->first_visible_x (0)
relative_x (55)
it->face_id (38)
foreground_face (magenta)
background_face (black)
rc (MOVE_X_REACHED)
I create the font pointer like this .... It has worked for everything so far
except this special character (U0001D4D5) on Emacs built --with-x. I believe
the face_id is correct in this example because the foreground (magenta) and
background (black) are correctly returned.
struct face *face = mc_lookup_face (it);
struct font *font = face->font;
Lisp_Object foreground_face = face->lface[LFACE_FOREGROUND_INDEX];
Lisp_Object background_face = face->lface[LFACE_BACKGROUND_INDEX];
... using the following function:
struct face *
mc_lookup_face (struct it *it)
{
if (!NILP (Vface_remapping_alist)
&& (it->face_id == DEFAULT_FACE_ID /* Qdefault */
|| it->face_id == MODE_LINE_FACE_ID /* Qmode_line */
|| it->face_id == MODE_LINE_INACTIVE_FACE_ID /* Qmode_line_inactive */
|| it->face_id == HEADER_LINE_FACE_ID /* Qheader_line */
|| it->face_id == TOOL_BAR_FACE_ID /* Qtool_bar */
|| it->face_id == FRINGE_FACE_ID /* Qfringe */
|| it->face_id == SCROLL_BAR_FACE_ID /* Qscroll_bar */
|| it->face_id == BORDER_FACE_ID /* Qborder */
|| it->face_id == CURSOR_FACE_ID /* Qcursor */
|| it->face_id == MOUSE_FACE_ID /* Qmouse */
|| it->face_id == MENU_FACE_ID /* Qmenu */
|| it->face_id == WINDOW_DIVIDER_FACE_ID /* Qwindow_divider */
|| it->face_id == WINDOW_DIVIDER_FIRST_PIXEL_FACE_ID /*
Qwindow_divider_first_pixel */
|| it->face_id == WINDOW_DIVIDER_LAST_PIXEL_FACE_ID /*
Qwindow_divider_last_pixel */
|| it->face_id == VERTICAL_BORDER_FACE_ID /* Qvertical_border */
|| it->face_id == INTERNAL_BORDER_FACE_ID)) /* Qinternal_border */
return FACE_FROM_ID (it->f, lookup_basic_face (it->f, it->face_id));
else
return FACE_FROM_ID (it->f, it->face_id);
}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DATE: [06-13-2018 12:11:33] <13 Jun 2018 22:11:33 +0300>
FROM: Eli Zaretskii <address@hidden>
>
> > Date: Wed, 13 Jun 2018 11:37:09 -0700
> > From: Keith David Bershatsky <address@hidden>
> >
> > I am working on crosshairs (17684) and multiple fake cursors (22873) and
> > created a little problem for myself in that a character not recognized by
> > the font (U0001D4D5) [aka a pretty letter f] on a line all by itself does
> > not have a font->space_width and causes Emacs to crash when printing said
> > value to STDERR.
> >
> > GDB returns "Cannot access memory at address 0xa0" when printing the value
> > of font->space_width.
>
> This message means that 'font' is a NULL pointer, and that is your
> basic problem. You need to find out why 'font' is NULL.