Function: char-before

char-before is a function defined in editfns.c.

Signature

(char-before &optional POS)

Documentation

Return character in current buffer preceding position POS.

POS is an integer or a marker and defaults to point. If POS is out of range, the value is nil.

Other relevant functions are documented in the buffer group.

View in manual

Shortdoc

;; buffer
(char-before 13)
    => 101

Source Code

// Defined in /usr/src/emacs/src/editfns.c
{
  register Lisp_Object val;
  register ptrdiff_t pos_byte;

  if (NILP (pos))
    {
      pos_byte = PT_BYTE;
      XSETFASTINT (pos, PT);
    }

  if (MARKERP (pos))
    {
      pos_byte = marker_byte_position (pos);

      if (pos_byte <= BEGV_BYTE || pos_byte > ZV_BYTE)
	return Qnil;
    }
  else
    {
      EMACS_INT p = fix_position (pos);

      if (! (BEGV < p && p <= ZV))
	return Qnil;

      pos_byte = CHAR_TO_BYTE (p);
    }

  if (!NILP (BVAR (current_buffer, enable_multibyte_characters)))
    {
      pos_byte -= prev_char_len (pos_byte);
      XSETFASTINT (val, FETCH_CHAR (pos_byte));
    }
  else
    {
      pos_byte--;
      XSETFASTINT (val, FETCH_BYTE (pos_byte));
    }
   return val;
}