csdn_文档中心_c++中的内部连接与外部连接(二).htm
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</SPAN>static int f() { return 2;}<SPAN
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</SPAN>//inline </SPAN><SPAN
style="COLOR: green; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类静态函数，内部连接</SPAN><SPAN
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN
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</SPAN><SPAN
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</SPAN>int g(int i) { return i;}<SPAN
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</SPAN>//inline </SPAN><SPAN
style="COLOR: green; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类成员函数，内部连接</SPAN><SPAN
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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</SPAN>class Base<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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</SPAN>public:<o:p></o:p></FONT></SPAN></P>
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</SPAN>inline int k()</SPAN><SPAN
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style="COLOR: green; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类成员函数声明，内部连接</SPAN><SPAN
lang=EN-US style="COLOR: green"><o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN
lang=EN-US style="COLOR: green"><SPAN
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</SPAN>}</SPAN><SPAN
style="COLOR: green; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US style="COLOR: green"><o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN
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</SPAN>inline int Base::k(){return 5;}<SPAN
style="mso-tab-count: 1"> </SPAN>//inline </SPAN><SPAN
style="COLOR: green; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类成员函数，内部连接</SPAN><SPAN
lang=EN-US style="COLOR: green"><o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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</SPAN>int main(void)<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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</SPAN>{<o:p></o:p></FONT></SPAN></P>
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</SPAN><SPAN
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</SPAN>return 0;<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-US
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</SPAN></SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如果你的</SPAN><SPAN
lang=EN-US>Base</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类是定义在</SPAN><SPAN
lang=EN-US>Base.h</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中，而</SPAN><SPAN
lang=EN-US>Base</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN
lang=EN-US>inline </SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数是在</SPAN><SPAN
lang=EN-US>Base.cpp</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中定义的，那么在</SPAN><SPAN
lang=EN-US>main.cpp</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中</SPAN><SPAN
lang=EN-US>include "Base.h"</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">编译不会出现问题，但在连接时会找不到函数</SPAN><SPAN
lang=EN-US>k</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，所以类的</SPAN><SPAN
lang=EN-US>inline</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数最好放到头文件中，让每一个包含头文件的</SPAN><SPAN
lang=EN-US>cpp</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">都能找到</SPAN><SPAN
lang=EN-US>inline</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数。</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN
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</FONT></SPAN></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">现在对</SPAN><SPAN
lang=EN-US>c++</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的连接有了一个认识，能清楚的知道是什么原因产生连接时错误。当你在连接时产生连接不到的错误，这说明所有的编译单元都没有这个实体的外部连接；当你在连接时发现有多个连接实体，这说明有多个编译单元提供了同名的有外部连接的实体。同时，在进行程序设计时，也要注意不要使只有本编译单元用到的函数、类、变量等有外部连接，减少与其它编译单元的连接冲突。</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN
lang=EN-US><FONT size=3> <o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">不过在这里没有说明</SPAN><SPAN
lang=EN-US>template</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数及</SPAN><SPAN
lang=EN-US>template class</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的连接性，并且对一些特别的情况也没有作出说明</SPAN><SPAN
lang=EN-US>(</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">比如</SPAN><SPAN
lang=EN-US>inline</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数不能被</SPAN><SPAN
lang=EN-US>inline)</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，欲知后事如何，且听下回分解</SPAN><SPAN
lang=EN-US> :)</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</SPAN></FONT></P><BR></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR>
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</SPAN> SpitFire <I>(2004-3-19 21:28:38)</I>
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<TD bgColor=#ffffff colSpan=3 width=532><BR>那只是一个声明，真正的定义在后面 int B::s_i =
0; //类静态数据成员定义，外部连接 <BR></TD></TR></TBODY></TABLE>
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</SPAN> iery <I>(2004-3-19 15:09:19)</I> </TD></TR>
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<TD bgColor=#ffffff colSpan=3 width=532><BR>//main.cpp class B //类定义，内部连接
{ static int s_i; //静态类成员声明，内部连接 public: void foo() { ++s_i;}
//类inline函数，内部连接 }; 好象不对，前一篇文章说"b)类静态成员变量总有外部连接。"
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