#pragma once: The #pragma once directive has a very simple concept. The header file containing this directive is included only once even if the programmer includes it multiple times during acompilation. This is not included in any ISO C++ standard. This directive works similar to the #include ...
#pragma once不是标准，通用性不那么强，但是即使不支持的编译器也仅仅忽略它，不会导致错误，这是标准...
} 【说明】:#pragma once并不是C++标准规定的,但是很多编译器都支持它。In the C and C++ programming languages, #pragma once is a non-standard but widely supported preprocessor directive designed to cause the current source file to be included only once in a single compilation. Thus, #pragma once...
} 【说明】:#pragma once并不是C++标准规定的,但是很多编译器都支持它。In the C and C++ programming languages, #pragma once is a non-standard but widely supported preprocessor directive designed to cause the current source file to be included only once in a single compilation. Thus, #pragma once...
【说明】：#pragma once并不是C++标准规定的，但是很多编译器都⽀持它。In the C and C++ programming languages, #pragma once is a non-standard but widely supported preprocessor directive designed to cause the current source file to be included only once in a single compilation. Thus, #pragma ...
So, should I use #pragma once or header guards? This question is a bit difficult to answer. Let’s take a look at the cons of each method: #pragma onceare non-standard and are a major issue when you end up in a degraded environment. ...
the include guard idiom and#pragma oncein the same file. The compiler recognizes the include guard idiom, and implements the multiple-include optimization the same way as the#pragma oncedirective if no non-comment code or preprocessor directive comes before or after the standard form of the ...
一直以为#pragma once只在VC中支持=_=,所以项目里头文件用的都是#ifndef直到今天翻C++11的书的时候,看到“在C/C++标准中,#pragma 是一条预处理的指令………定义了以下语句 #pragma once……”这句话,才知道#pragma once貌似是符合标准的。。。使用VS2015,TDM-GCC 5.1 ,GCC(Ubuntu) 4.8 都能通过编译。。然...
It isn't part of the C++ Standard, but it's implemented portably by several common compilers.There's no advantage to use of both the include guard idiom and #pragma once in the same file. The compiler recognizes the include guard idiom, and implements the multiple-include optimization the ...
What does #pragma once mean in C? [duplicate] Solution 1: The #pragma once preprocessor directive is extensively supported but not standard in the C and C++ programming languages. Its function is to ensure that the current source file is included only once in a single compilation. #pragma on...