copy and paste this google map to your website or blog!
Press copy button and paste into your blog or website.
(Please switch to 'HTML' mode when posting into your blog. Examples: WordPress Example, Blogger Example)
Input Form:Deal with this potential dealer,buyer,seller,supplier,manufacturer,exporter,importer
(Any information to deal,buy, sell, quote for products or service)
#ifdef and #ifndef directives (C C++) | Microsoft Learn The #ifdef identifier statement is equivalent to #if 1 when identifier has been defined It's equivalent to #if 0 when identifier hasn't been defined, or has been undefined by the #undef directive
What is the purpose of using #ifdef and #if in C++? #ifdef means if defined If the symbol following #ifdef is defined, either using #define in prior source code or using a compiler command-line argument, the text up to the enclosing #endif is included by the preprocessor and therefore compiled
C语言#ifdef和#ifndef命令的用法（非常详细） #ifdef 是 if defined 的缩写，也即“是否定义”的意思；#ifndef 是 if not defined 的缩写，也即“是否未定义”的意思。 它们会根据「某个宏是否被定义」来控制代码的编译过程。
Ifdef (The C Preprocessor) You can do this by writing ‘ #ifndef ’ instead of ‘ #ifdef ’ One common use of ‘ #ifndef ’ is to include code only the first time a header file is included
Conditional inclusion - cppreference. com The conditional preprocessing block starts with #if, #ifdef or #ifndef directive, then optionally includes any number of #elif, #elifdef, or #elifndef(since C++23) directives, then optionally includes at most one #else directive and is terminated with #endif directive
#ifdef, #ifndef and ## Preprocessors - An Expert‘s Guide for C . . . Directives like #ifdef, #ifndef and ## provide text substitution capabilities that would otherwise require littering core logic flows Learning to wield them tastefully is an essential skill for any serious C developer
#ifdef statement : Conditional Compilation Directives (C Preprocessor) We say that the conditional succeeds if MACRO is defined, fails if it is not The MACRONAME inside of a conditional can include preprocessing directives They are executed only if the conditional succeeds You can nest conditional groups inside other conditional groups, but they must be completely nested
Understanding Ifdef C++: A Quick Guide - cppscripts. com `#ifdef` stands for "if defined " It is a preprocessor directive that checks if a particular macro has been defined If the macro is defined, the code within the `#ifdef` block gets included in the compilation process; otherwise, it is ignored