• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>
            aurain
            技術文摘
            posts - 137,  comments - 268,  trackbacks - 0

            Tells the compiler that the declared global data item (variable or object) is a pick-any COMDAT (a packaged function).


            __declspec( selectany ) declarator
            

            At link time, if multiple definitions of a COMDAT are seen, the linker picks one and discards the rest. If the linker option /OPT:REF (Optimizations) is selected, then COMDAT elimination will occur to remove all the unreferenced data items in the linker output.

            Constructors and assignment by global function or static methods in the declaration do not create a reference and will not prevent /OPT:REF elimination. Side effects from such code should not be depended on when no other references to the data exist.

            For dynamically initialized, global objects, selectany will discard an unreferenced object's initialization code, as well.

            A global data item can normally be initialized only once in an EXE or DLL project. selectany can be used in initializing global data defined by headers, when the same header appears in more than one source file. selectany is available in both the C and C++ compilers.


            //Correct - x1 is initialized and externally visible 
            __declspec(selectany) int x1=1;
            
            //Incorrect - const is by default static in C++, so 
            //x2 is not visible externally (This is OK in C, since
            //const is not by default static in C)
            const __declspec(selectany) int x2 =2;
            
            //Correct - x3 is extern const, so externally visible
            extern const __declspec(selectany) int x3=3;
            
            //Correct - x4 is extern const, so it is externally visible
            extern const int x4;
            const __declspec(selectany) int x4=4;
            
            //Incorrect - __declspec(selectany) is applied to the uninitialized
            //declaration of x5
            extern __declspec(selectany) int x5;
            
            // OK: dynamic initialization of global object
            class X {
            public:
            X(int i){i++;};
            int i;
            };
            
            __declspec(selectany) X x(1);
            

            This code shows how to use the selectany attribute to ensure data COMDAT folding when you also use the /OPT:ICF linker option. Note that data must be marked with selectany and placed in a const (readonly) section. You must explicitly specify the read-only section.

            // selectany2.cpp
            // in the following lines, const marks the variables as read only
            __declspec(selectany) extern const int ix = 5;
            __declspec(selectany) extern const int jx = 5;
            int main() {
               int ij;
               ij = ix + jx;
            }
            

             

            posted on 2013-01-14 00:03 閱讀(632) 評論(0)  編輯 收藏 引用 所屬分類: vc

            <2013年1月>
            303112345
            6789101112
            13141516171819
            20212223242526
            272829303112
            3456789

            常用鏈接

            留言簿(17)

            隨筆分類(138)

            隨筆檔案(137)

            網絡開發

            最新隨筆

            搜索

            •  

            積分與排名

            • 積分 - 499423
            • 排名 - 36

            最新隨筆

            最新評論

            閱讀排行榜

            評論排行榜

            国产亚洲精品美女久久久| 婷婷综合久久狠狠色99h| 久久精品国产亚洲AV香蕉| 久久久久人妻精品一区二区三区 | 无码精品久久久天天影视| 精品久久久噜噜噜久久久 | 日本免费久久久久久久网站| 久久国产高清字幕中文| 久久人人爽人人爽人人片AV麻烦| 无码精品久久久久久人妻中字| 999久久久免费精品国产| 国产精品亚洲综合久久| 久久精品视频91| 麻豆成人久久精品二区三区免费 | 欧美成人免费观看久久| 韩国三级中文字幕hd久久精品| 久久99国产精品尤物| 精品无码久久久久久国产| 漂亮人妻被黑人久久精品| 日韩电影久久久被窝网| 99久久精品免费国产大片| 亚洲αv久久久噜噜噜噜噜| 久久精品夜色噜噜亚洲A∨| 国产成人久久激情91| 7777久久久国产精品消防器材| 精品久久人人爽天天玩人人妻| 国内精品久久久久国产盗摄| 午夜天堂av天堂久久久| 欧美亚洲国产精品久久| 婷婷久久综合| 欧美一级久久久久久久大| 久久激情五月丁香伊人| 国产综合免费精品久久久| 免费观看成人久久网免费观看| 久久ww精品w免费人成| 久久精品国产亚洲av水果派| 精品久久久中文字幕人妻| 午夜不卡久久精品无码免费| 久久久久久综合网天天| 午夜久久久久久禁播电影| 久久久久久国产精品无码超碰|