ckground: white;">color: blue; line-height: 150%; font-family: Verdana;">1 color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">基本解释color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">可以置于变量或者color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">前࿰c;以标示变量或者color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的定义在别的文件中࿰c;提示class="tags" href="/tags/BianYiQi.html" title=编译器>编译器遇到此变量和color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">时在其他模块中寻找其定义。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　另外࿰c;color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">也可用来进行链接指定。color: blue; line-height: 150%; font-family: Verdana;">

ckground: white;">color: blue; line-height: 150%; font-family: Verdana;">2 color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">问题：color: blue; line-height: 150%; font-family: Verdana;">extern color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">变量color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　在一个源文件里定义了一个数组：color: blue; line-height: 150%; font-family: Verdana;">char a[6];
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　在另外一个文件里用下列语句进行了声明：color: blue; line-height: 150%; font-family: Verdana;">extern char *acolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">；color: blue; line-height: 150%; font-family: Verdana;">
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　请问࿰c;这样可以吗？color: blue; line-height: 150%; font-family: Verdana;" lang="ZH-CN"> color: blue; line-height: 150%; font-family: Verdana;">

ckground: white; margin-bottom: 14pt;">color: blue; line-height: 150%; font-family: Verdana;">
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　答案与分析：color: blue; line-height: 150%; font-family: Verdana;">
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">1)color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">、不可以࿰c;程序运行时会告诉你非法访问。原因在于࿰c;指向类型color: blue; line-height: 150%; font-family: Verdana;">Tcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">指针color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">并不等价于类型color: blue; line-height: 150%; font-family: Verdana;">Tcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的数组。color: blue; line-height: 150%; font-family: Verdana;">extern char *acolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">声明的是一个color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">指针color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">变量而不是字符数组࿰c;因此与实际的定义不同࿰c;从而造成运行时非法访问。应该将声明改为color: blue; line-height: 150%; font-family: Verdana;">extern char a[ ]color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">2)color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">、例子分析如下࿰c;如果color: blue; line-height: 150%; font-family: Verdana;">a[] = "abcd",color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">则外部变量color: blue; line-height: 150%; font-family: Verdana;">a=0x61626364 (abcdcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的color: blue; line-height: 150%; font-family: Verdana;">ASCIIcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">码值color: blue; line-height: 150%; font-family: Verdana;">)color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">࿰c;color: blue; line-height: 150%; font-family: Verdana;">*acolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">显然没有意义color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　显然color: blue; line-height: 150%; font-family: Verdana;">acolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">指向的空间（color: blue; line-height: 150%; font-family: Verdana;">0x61626364color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">）没有意义࿰c;易出现非法内存访问。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">3)color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">、这提示我们࿰c;在使用color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">时候要严格对应声明时的格式࿰c;在实际编程中࿰c;这样的错误屡见不鲜。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">4)color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">、color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">用在变量声明中常常有这样一个作用࿰c;你在color: blue; line-height: 150%; font-family: Verdana;">*.ccolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">文件中声明了一个全局的变量࿰c;这个全局的变量如果要被引用࿰c;就放在color: blue; line-height: 150%; font-family: Verdana;">*.hcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">中并用color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">来声明。color: blue; line-height: 150%; font-family: Verdana;">

ckground: white;">color: blue; line-height: 150%; font-family: Verdana;">4 color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">问题：color: blue; line-height: 150%; font-family: Verdana;">extern color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数2

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　当color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">提供方单方面修改color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">原型时࿰c;如果使用方不知情继续沿用原来的color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">申明࿰c;这样编译时class="tags" href="/tags/BianYiQi.html" title=编译器>编译器不会报错。但是在运行过程中࿰c;因为少了或者多了输入参数࿰c;往往会照成系统错误࿰c;这种情况应该如何解决？color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　答案与分析：color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　目前业界针对这种情况的处理没有一个很完美的方案࿰c;通常的做法是提供方在自己的color: blue; line-height: 150%; font-family: Verdana;">xxx_pub.hcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">中提供对外部color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">接口color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的声明࿰c;然后调用方color: blue; line-height: 150%; font-family: Verdana;">class="tags" href="/tags/INCLUDE.html" title=include>includecolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">该头文件࿰c;从而省去color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">这一步。以避免这种错误。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　宝剑有双锋࿰c;对color: blue; line-height: 150%; font-family: Verdana;">externcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的应用࿰c;不同的场合应该选择不同的做法。color: blue; line-height: 150%; font-family: Verdana;">

ckground: white;">color: blue; line-height: 150%; font-family: Verdana;">5 color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">问题：color: blue; line-height: 150%; font-family: Verdana;">extern “C”

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　在color: blue; line-height: 150%; font-family: Verdana;">color: blue;">C++color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">环境下使用color: blue; line-height: 150%; font-family: Verdana;">Ccolor: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的时候࿰c;常常会出现class="tags" href="/tags/BianYiQi.html" title=编译器>编译器无法找到color: blue; line-height: 150%; font-family: Verdana;">objcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">模块中的color: blue; line-height: 150%; font-family: Verdana;">Ccolor: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">定义࿰c;从而导致链接失败的情况࿰c;应该如何解决这种情况呢？color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　答案与分析：color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　color: blue; line-height: 150%; font-family: Verdana;">color: blue;">C++color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">class="tags" href="/tags/YuYan.html" title=语言>语言在编译的时候为了解决color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的多态问题࿰c;会将color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">名和参数联合起来生成一个中间的color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">名称࿰c;而color: blue; line-height: 150%; font-family: Verdana;">color: blue;">Ccolor: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">class="tags" href="/tags/YuYan.html" title=语言>语言color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">则不会࿰c;因此会造成链接时找不到对应color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的情况࿰c;此时color: blue; line-height: 150%; font-family: Verdana;">Ccolor: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">就需要用color: blue; line-height: 150%; font-family: Verdana;">extern “C”color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">进行链接指定࿰c;这告诉class="tags" href="/tags/BianYiQi.html" title=编译器>编译器࿰c;请保持我的名称࿰c;不要给我生成用于链接的中间color: blue; line-height: 150%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">名。color: blue; line-height: 150%; font-family: Verdana;">

color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　下面是一个标准的写法：color: blue; line-height: 150%; font-family: Verdana;">

//color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">在color: blue; line-height: 150%; font-family: Verdana;">.hcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">文件的头上color: blue; line-height: 150%; font-family: Verdana;">
#ifdef __cplusplus
#if __cplusplus
extern "C"{
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">#endif
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">#endif /* __cplusplus */
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">…
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">…
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">//.hcolor: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">文件结束的地方color: blue; line-height: 150%; font-family: Verdana;">
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">#ifdef __cplusplus
color: blue; line-height: 150%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　color: blue; line-height: 150%; font-family: Verdana;">#if __cplusplus
}
#endif
#endif /* __cplusplus */ 

class="MsoNormal" style="background: white; margin: 0in 0in 7.5pt; line-height: 130%;">color: blue; line-height: 130%; font-family: Verdana;">3 color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">问题：color: blue; line-height: 130%; font-family: Verdana;">extern color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数1

color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　常常见color: blue; line-height: 130%; font-family: Verdana;">externcolor: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">放在color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的前面成为color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">声明的一部分࿰c;那么࿰c;color: blue; line-height: 130%; font-family: Verdana;">color: blue;">Ccolor: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">class="tags" href="/tags/YuYan.html" title=语言>语言color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的关键字color: blue; line-height: 130%; font-family: Verdana;">externcolor: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">在color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的声明中起什么作用？color: blue; line-height: 130%; font-family: Verdana;">

color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　答案与分析：color: blue; line-height: 130%; font-family: Verdana;">

color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　如果color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">的声明中带有关键字color: blue; line-height: 130%; font-family: Verdana;">externcolor: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">࿰c;仅仅是暗示这个color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">可能在别的源文件里定义࿰c;没有其它作用。即下述两个color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">声明没有明显的区别：color: blue; line-height: 130%; font-family: Verdana;">

extern int f(); color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">和color: blue; line-height: 130%; font-family: Verdana;">int f();
color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">　　当然࿰c;这样的用处还是有的࿰c;就是在程序中取代color: blue; line-height: 130%; font-family: Verdana;">class="tags" href="/tags/INCLUDE.html" title=include>include “*.h”color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">来声明color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">࿰c;在一些复杂的项目中࿰c;我比较习惯在所有的color: blue; line-height: 130%; font-family: Verdana;">color: blue; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">函数color: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">声明前添加color: blue; line-height: 130%; font-family: Verdana;">externcolor: blue; line-height: 130%; font-family: 宋体; mso-ascii-font-family: Verdana; mso-hansi-font-family: Verdana;" lang="ZH-CN">修饰。color: blue; line-height: 130%; font-family: Verdana;">