I finally solve it :
- (BOOL)isCharacter:(unichar)character supportedByFont:(UIFont *)aFont
{
UniChar characters[] = { character };
CGGlyph glyphs[1] = { };
CTFontRef ctFont = CTFontCreateWithName((CFStringRef)aFont.fontName, aFont.pointSize, NULL);
BOOL ret = CTFontGetGlyphsForCharacters(ctFont, characters, glyphs, 1);
CFRelease(ctFont);
return ret;
}