c#include指令中使用..(点点)是否合法？

那里.正如标题所说.
使用#include“test.h”是合法的.
使用#include“test / test.h”也是合法的.
但使用#include“../ test.h”是否合法？

例如,#pragma once几乎在每个编译器中都是合法的.
但这不是C的标准.

我找不到任何说“保证”是父目录含义的文件.
谁能帮我？

解决方法:

C标准在§2.8/ 1中说：

Header name preprocessing tokens shall only appear within a #include
preprocessing directive (16.2). The sequences in both forms of
header-names are mapped in an implementation-defined manner to headers
or to external source file names as specified in 16.2.

所以在这里你拥有它：它是所有实现定义的.然后§16.2说,在与你的问题没有直接关系的其他一些事情中：

A preprocessing directive of the form

#include "q-char-sequence" new-line

causes the replacement of that directive by the entire contents of the
source file identified by the specified sequence between the "
delimiters. The named source file is searched for in an
implementation-defined manner.

这很有道理.为什么不能为不使用“..”约定的文件系统创建C编译器？

总而言之,回答你的问题：是的,根据C标准它是合法的,但这并不奇怪,因为几乎所有的东西在技术上都符合#include指令.

更有趣的问题是你的C实现的文档对此有何看法.但即便如此,您可能会对该主题留下相当通用的解释.例如,MSVC 2015 documentation for #include说：

The path-spec is a file name that may optionally be preceded by a
directory specification. The file name must name an existing file. The
syntax of the path-spec depends on the operating system on which the
program is compiled.

标签：c,include,include-path
来源： https://codeday.me/bug/20190829/1760949.html