联动期间外部函数？ [英] extern function during linkage?

问题描述

我有这种奇怪的事情：

在file1.c中有

extern void foo(int x, int y);
..
..

int tmp = foo(1,2);

在这个项目我能找到的只有这富（）：

in the project I could find only this foo():

在file2.c中：

int foo(int x, int y, int z)
{
....
}

在file2.h：

int foo(int x, int y, int z);

file2.h不包括在file1.c中（这就是为什么谁写的使用的extern，我猜）。

file2.h isn't included in file1.c (this is why who wrote it used extern, i guess).

该项目编译好，我想这是因为在file1.c中富（）将被找只在联动，对吗？

this project compiles fine, I think that's because in file1.c foo() will be looked for only during linkage, am I right?

但我真正的问题是：为什么是联动succssful？
毕竟，有与2个参数富无此功能....
而我在C ..所以没有超载。

but my real question is : why is the linkage succssful ? after all, there is no such function as foo with 2 parameters.... and i'm in c .. so there's no overloading..

所以这是怎么回事？

推荐答案

由于没有超载，C编译器不装饰函数名。链接器在 file2.c中找到一个参考的作用富和 file1.c中它找到一个函数富。它可以不知道自己的参数列表不匹配，并愉快地使用它们。

Because there is no overloading, the C compiler does not decorate the function names. The linker finds in file2.c a reference to function foo and in file1.c it finds a function foo. It cannot know their parameter lists do not match and happily use them.

当然，当函数富运行以Z 的值是垃圾和程序的行为变得未predictable从这一点上。

Of course, when the function foo runs the value of z is garbage and the behavior of the program becomes unpredictable from that point on.

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