Referencing Unicode characters

SP(code point x20)
.(code point x2e)
0(code point x30)
▶(code point x25B6)
.(code point 46)
/(code point 47)
0(code point 48)

HTML (1993)

  – 1 (SP not rendered by browser):

! " # $ % & ' ( ) * + , - . / 0 1

@hexadecimal reference: @
@"
@decimal reference: @
@"
`decimal reference: `
:(&#0x40;interpreted as the string '&#0x40;'
:(&#o100;interpreted as the string '&#o100;'

CSS (1996)

A test using ::before { content:'\40\20'; }

'\40'hexadecimal reference: @
'\040'"
:('\x040'interpreted as the string 'x040'
:('x040'"

C programming (1972)

Rules for determining the radix of an integer constant
begins withexampleunderstood as
0x0x40hexadecimal
0 but not 0x0100octal
digit 1-964decimal

Summary

To refer to a Unicode character:
languagerefer to '▶'alternative notations
C0x25b6hexadecimal, octal, decimal
HTML▶hexadecimal, decimal
CSS'\25b6'hexadecimal