You are defining a function with external linkage and including it in two compilation units.

你定义的函数与外部的联系，包括这两个编译单元。

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The point is as follows: First, procedure declarations and function declarations are treated as compilation units.

要点是首先把过程说明和函数说明处理作编译单位。

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Then the compilation units which need not to be checked are pruned away so that the pruned source program is compiled.

然后压缩去源程序中无需语法检查的编译单位，从而对压缩过的源程序进行编译。

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