Function
dwarf_formexprloc()
allows an application to retrieve the length and the bytes of a
DWARF location expression.
Argument
attr
should reference a DWARF attribute of the form
DW_FORM_exprloc.
Argument
retlen
should point to a location that will be set to the length of the
location expression.
Argument
retexpr
should point to a location that will be set to a pointer to the
content of the location expression itself.
If argument
err
is not NULL, it will be used to return an error descriptor in case
of an error.