16,471
社区成员
发帖
与我相关
我的任务
分享========内联函数返回值的问题，不报错==============
以前没有注意过，今天用内联函数的时候，忘记了写返回值。VS2005竟然不报错。
如果把inline 去掉，就会报错。
加上inline 就不会报错。
inline BOOL testfun();
inline BOOL CTest::testfun()
{
}
//以上不报错。下面这样就报错。
BOOL testfun();
BOOL CTest::testfun()
{
}
这个是VS2005的bug，还是什么原因？
如果把inline 去掉，就会报错。
加上inline 就不会报错。
inline BOOL testfun();
inline BOOL CTest::testfun()
{
}
//以上不报错。下面这样就报错。
BOOL testfun();
BOOL CTest::testfun()
{
}
这个是VS2005的bug，还是什么原因？
...全文
请发表友善的回复…
发表回复
zgsdzhaolanxiang1 2010-11-14
- 打赏
- 举报
高人。。。。。。。
信阳毛尖 2010-11-14
- 打赏
- 举报
这个还真不清楚......
wltg2001 2010-11-14
- 打赏
- 举报
内联函数有点类似于宏的概念，它并不是真正的函数，函数在执行时是要将指令跳转到函数入口处的，但内联函数是在编译时将它插入到源代码调用它的地方。
MoXiaoRab 2010-11-14
- 打赏
- 举报
你没有理解Inline函数的底层原理，如果你看过编译器的逆向代码就能看到
下面引用一段大牛的话：
Using functions saves memory space because all the calls to a particular function execute the same code, which is provided only once. However, there is an overhead due to the extra time required to jump to the point that the instructions of that function are provided and then return back to the invocation point. In some cases, where very small functions are used repeatedly, it may be more efficient to have the code incorporated at the point of the function call instead of actually calling the function, so as to avoid the associated overhead. Inline functions can be used for this purpose. An inline function is a regular function with a suggestion to the compiler to insert the instructions at the points where the function is called.
A definition of a function as inline suggests to the compiler to expand the body of the function at all points where it is invoked. An inline function is expanded by the compiler during the compilation phase and not by the preprocessor (during macro substitutions). This is useful for very short functions which may result in a computational overhead whenever they are called. Inline functions eliminate the overhead of function calls while allowing the usage of procedural abstraction.
简单的说，inline函数和其他函数的不同，执行快不假，但是也有其自身的限制
此外，inline函数的声明中的函数体将被编译器展开，当执行到这个inline函数的时候，跳转过来，执行完毕函数体后，再跳转回去。
可以说，甚至不是真正意义上的函数，而是一段独立的代码。在跳转的过程中，符号就起到了很大的作用。
所以，在C++设计编译器的时候，大牛们就是这么想的，内联函数不返回值也可以
下面引用一段大牛的话：
Using functions saves memory space because all the calls to a particular function execute the same code, which is provided only once. However, there is an overhead due to the extra time required to jump to the point that the instructions of that function are provided and then return back to the invocation point. In some cases, where very small functions are used repeatedly, it may be more efficient to have the code incorporated at the point of the function call instead of actually calling the function, so as to avoid the associated overhead. Inline functions can be used for this purpose. An inline function is a regular function with a suggestion to the compiler to insert the instructions at the points where the function is called.
A definition of a function as inline suggests to the compiler to expand the body of the function at all points where it is invoked. An inline function is expanded by the compiler during the compilation phase and not by the preprocessor (during macro substitutions). This is useful for very short functions which may result in a computational overhead whenever they are called. Inline functions eliminate the overhead of function calls while allowing the usage of procedural abstraction.
简单的说，inline函数和其他函数的不同，执行快不假，但是也有其自身的限制
此外，inline函数的声明中的函数体将被编译器展开，当执行到这个inline函数的时候，跳转过来，执行完毕函数体后，再跳转回去。
可以说，甚至不是真正意义上的函数，而是一段独立的代码。在跳转的过程中，符号就起到了很大的作用。
所以，在C++设计编译器的时候，大牛们就是这么想的，内联函数不返回值也可以
virtualcode 2010-11-14
- 打赏
- 举报
占座。
同问
同问
