set-face-italic

set-face-italic is a compiled Lisp function in `faces.el'.

(set-face-italic FACE ITALIC-P &optional FRAME)

Specify whether face FACE is italic.
ITALIC-P non-nil means FACE should explicitly display italic.
ITALIC-P nil means FACE should explicitly display non-italic.
FRAME nil or not specified means change face on all frames.
Use `set-face-attribute' or `modify-face' for finer control.