Function: face-attribute-relative-p
face-attribute-relative-p is a function defined in xfaces.c.
Signature
(face-attribute-relative-p ATTRIBUTE VALUE)
Documentation
Check whether a face attribute value is relative.
Specifically, this function returns t if the attribute ATTRIBUTE with the value VALUE is relative.
A relative value is one that doesn't entirely override whatever is
inherited from another face. For most possible attributes,
the only relative value that users see is unspecified.
However, for :height, floating point values are also relative.
Probably introduced at or before Emacs version 22.1.
Source Code
// Defined in /usr/src/emacs/src/xfaces.c
{
if (EQ (value, Qunspecified) || (EQ (value, QCignore_defface)))
return Qt;
else if (EQ (attribute, QCheight))
return FIXNUMP (value) ? Qnil : Qt;
else
return Qnil;
}