内联限定词源自原型或定义？ [英] Inline qualifier stems from prototype or definition?

问题描述

我不太确定这在标准。假设我有三个档案，例如：

I'm not quite sure about this in the standards. Say I have three files like this:

foo.h

#include <iostream>

inline void foo();

void foo()
{
   std::cout << "Foo" << std::endl;
}

foo.cpp： b
$ b

foo.cpp:

#include "foo.h"

void baz();

int main()
{
   baz();
   foo();
}

bar.cpp
$ b

bar.cpp

#include "foo.h"

void baz()
{
   foo();
}

现在，foo的定义将被编译成两个编译单元foo.o和bar.o.如果我理解它正确，内联函数将避免链接器collition。 G ++编译和链接这只是很好，但与clang ++ 2.8我得到这个错误：

Now, the definition for foo will be compiled into both compilation units foo.o and bar.o. If I understand it correctly, having inlined functions will avoid linker collition. G++ compiled and links this just fine, but with clang++ 2.8 I get this error:

/tmp/cc-7RdmYP.o: In function `foo()':
bar.cpp:(.text+0x50): multiple definition of `foo()'
/tmp/cc-LW3id3.o:foo.cpp:(.text+0x50): first defined here
collect2: ld returned 1 exit status

clang ++看不到 void foo（）作为内联函数。然而，它确实工作正常，当我添加内联的定义以及。

It seems that clang++ does not see void foo() as an inlined function. It does however, work fine when I add inline to the definition as well.

我必须在 void foo（）中添加内联，以便将其视为内联函数，或者是一个clang ++错误？

Do I have to add inline to void foo() as well here to have it be seen as an inlined function, or is this a clang++ bug?

推荐答案

C ++ 0X draft N3225在 2函数说明符：

C++0X draft N3225 says in 7.1.2 Function specifiers:

• 语句2：内联函数


• 第4条：内联函数应在其使用的每个转换单元中定义，完全相同的定义在每种情况下。

• clause 2: A function declaration with an inline specifier declares an inline function
• clause 4: An inline function shall be defined in every translation unit in which it is odr-used and shall have exactly the same definition in every case.

; clang错误，但仍有一个（slim）的机会，在C ++ 03中的东西是不同的。

So, to me, it looks like gcc is right & clang wrong, but there's still a (slim) chance that things were (are?) different in C++03..

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