求模版函数地址

最近用 WTL 写 Ribbon 界面,发现一个坑。

先看 WTL9.1 的代码

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static void (CharFormat::*Getk_[])(IPropertyStore*) = 
{
&CharFormat::Getk_Family,
&CharFormat::Getk_FontProperties_Size,
&CharFormat::Getk_MaskEffect<CFM_BOLD, CFE_BOLD, UI_PKEY_FontProperties_Bold>,
&CharFormat::Getk_MaskEffect<CFM_ITALIC, CFE_ITALIC, UI_PKEY_FontProperties_Italic>,
&CharFormat::Getk_MaskEffect<CFM_UNDERLINE, CFE_UNDERLINE, UI_PKEY_FontProperties_Underline>,
&CharFormat::Getk_MaskEffect<CFM_STRIKEOUT, CFE_STRIKEOUT, UI_PKEY_FontProperties_Strikethrough>,
&CharFormat::Getk_VerticalPositioning,
&CharFormat::Getk_Color<CFM_COLOR, UI_PKEY_FontProperties_ForegroundColor>,
&CharFormat::Getk_Color<CFM_BACKCOLOR, UI_PKEY_FontProperties_BackgroundColor>,
&CharFormat::Getk_ColorType<CFM_COLOR, CFE_AUTOCOLOR, UI_SWATCHCOLORTYPE_AUTOMATIC, UI_PKEY_FontProperties_ForegroundColorType>,
&CharFormat::Getk_ColorType<CFM_BACKCOLOR, CFE_AUTOBACKCOLOR, UI_SWATCHCOLORTYPE_NOCOLOR, UI_PKEY_FontProperties_BackgroundColorType>,
};

其中 Getk_MaskEffect 是个模版函数,实现如下:

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template <DWORD t_dwMask, DWORD t_dwEffects, REFPROPERTYKEY key>
void Getk_MaskEffect(IPropertyStore* pStore)
{
if (SUCCEEDED(pStore->GetValue(key, &propvar)))
{
UIPropertyToUInt32(key, propvar, &uValue);
if ((UI_FONTPROPERTIES)uValue != UI_FONTPROPERTIES_NOTAVAILABLE)
{
dwMask |= t_dwMask;
dwEffects |= ((UI_FONTPROPERTIES) uValue == UI_FONTPROPERTIES_SET) ? t_dwEffects : 0;
}
}
}

然后,在 VS2017 编译失败了……

1>X:\WTL91_5321_Final\Include\atlribbon.h(422): error C2440: ‘initializing’: cannot convert from ‘overloaded-function’ to ‘void (__thiscall WTL::RibbonUI::CharFormat:: )(IPropertyStore )’

1>X:\WTL91_5321_Final\Include\atlribbon.h(422): note: None of the functions with this name in scope match the target type

然后根据错误提示搜到:Cannot take address of template function,https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39018,翻译一下:模版函数的地址转化,分两步走,第一步先转具化,第二步转目标类型,这样可以;直接转过去不可以!

再来看看 WTL10 怎么解决这个问题的!

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static void (CharFormat::*Getk_[])(IPropertyStore*) = 
{
&CharFormat::Getk_Family,
&CharFormat::Getk_FontProperties_Size,
&CharFormat::Getk_MaskEffectBold,
&CharFormat::Getk_MaskEffectItalic,
&CharFormat::Getk_MaskEffectUnderline,
&CharFormat::Getk_MaskEffectStrikeout,
&CharFormat::Getk_VerticalPositioning,
&CharFormat::Getk_Color,
&CharFormat::Getk_ColorBack,
&CharFormat::Getk_ColorType,
&CharFormat::Getk_ColorTypeBack,
};

原来的模版函数,已经替换成普通函数了……

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void Getk_MaskEffectBold(IPropertyStore* pStore)
{
Getk_MaskEffectAll(pStore, CFM_BOLD, CFE_BOLD, UI_PKEY_FontProperties_Bold);
}

void Getk_MaskEffectItalic(IPropertyStore* pStore)
{
Getk_MaskEffectAll(pStore, CFM_ITALIC, CFE_ITALIC, UI_PKEY_FontProperties_Italic);
}

void Getk_MaskEffectUnderline(IPropertyStore* pStore)
{
Getk_MaskEffectAll(pStore, CFM_UNDERLINE, CFE_UNDERLINE, UI_PKEY_FontProperties_Underline);
}

void Getk_MaskEffectStrikeout(IPropertyStore* pStore)
{
Getk_MaskEffectAll(pStore, CFM_STRIKEOUT, CFE_STRIKEOUT, UI_PKEY_FontProperties_Strikethrough);
}

void Getk_MaskEffectAll(IPropertyStore* pStore, DWORD _dwMask, DWORD _dwEffects, REFPROPERTYKEY key)
{
if (SUCCEEDED(pStore->GetValue(key, &propvar)))
{
UIPropertyToUInt32(key, propvar, &uValue);
if ((UI_FONTPROPERTIES)uValue != UI_FONTPROPERTIES_NOTAVAILABLE)
{
dwMask |= _dwMask;
dwEffects |= ((UI_FONTPROPERTIES)uValue == UI_FONTPROPERTIES_SET) ? _dwEffects : 0;
}
}
}