Ifdef C++

#Diretivas if, #elif, #else e #endif (C/C++) | Microsoft Docs

docs.microsoft.com#ifdef identificador de #ifdef … Em C++, em que as classes geralmente são definidas em arquivos de cabeçalho, construções como esta podem ser usadas para impedir várias definições: In C++, where classes are often defined in header files, constructs like this one can be used to prevent multiple definitions: /* EXAMPLE.H – Example header file */ #if !defined( EXAMPLE_H ) #define EXAMPLE …

https://docs.microsoft.com/pt-br/cpp/preprocessor/hash-if-hash-elif-hash-else-and-hash-endif-directives-c-cpp

#ifndef – C and C++ Syntax Reference – Cprogramming.com

cprogramming.com#ifndef checks whether the given token has been #defined earlier in the file or in an included file; if not, it includes the code between it and the closing #else or, if no #else is present, #endif statement. #ifndef is often used to make header files idempotent by defining a token once the file has been included and checking that the token was not set at the top of that file.

https://www.cprogramming.com/reference/preprocessor/ifndef.html

Preprocessor directives – C++ Tutorials

cplusplus.com#ifndef __cplusplus#error A C++ compiler is required!#endif This example aborts the compilation process if the macro name __cplusplusis not defined (this macro name is defined by default in all C++ compilers). Source file inclusion (#include) This directive has been used assiduously in other sections of this tutorial.

https://www.cplusplus.com/doc/tutorial/preprocessor/

Ifdef (The C Preprocessor)

gcc.gnu.org#ifdef MACRO controlled text #endif /* MACRO */ This block is called a conditional group. controlled text will be included in the output of the preprocessor if and only if MACRO is defined. We say that the conditional succeeds if MACRO is defined, fails if it is not. The controlled text inside of a conditional can include preprocessing directives.

https://gcc.gnu.org/onlinedocs/cpp/Ifdef.html

Replacing text macros – cppreference.com

en.cppreference.com2020-09-20 · Otherwise, the behavior is undefined. [] # and ## operatorIn function-like macros, a # operator before an identifier in the replacement-list runs the identifier through parameter replacement and encloses the result in quotes, effectively creating a string literal. In addition, the preprocessor adds backslashes to escape the quotes surrounding embedded string literals, if any, and doubles the …

https://en.cppreference.com/w/cpp/preprocessor/replace

c preprocessor – How to add a ‘or’ condition in #ifdef …

stackoverflow.comCombining C++ and C – how does #ifdef __cplusplus work? 2. Finding printf() calls outside #ifdef statements using Regex (POSIX) 3. Code complexity metrics and ifdefs. 8. Advantages of conditional-preprocessor over conditional statements. 1. How to count how many #ifdef clauses have at least an #elif but no #else in a set of C files? 8. Can #if conditional areas cross include file boundaries? 2 …

https://stackoverflow.com/questions/2998864/how-to-add-a-or-condition-in-ifdef

C Language: #ifdef Directive – techonthenet.com

techonthenet.comIn the C Programming Language, the #ifdef directive allows for conditional compilation. The preprocessor determines if the provided macro exists before including the subsequent code in the compilation process.

https://www.techonthenet.com/c_language/directives/ifdef.php

Conditional Compilation (#if, #ifdef, #ifndef, #else,…# …

cs.auckland.ac.nz8.2 Conditional Compilation (#if, #ifdef, #ifndef, #else, #elif, #endif, and defined) Six directives are available to control conditional compilation. They delimit blocks of program text that are compiled only if a specified condition is true. These directives can be nested.

https://www.cs.auckland.ac.nz/references/unix/digital/AQTLTBTE/DOCU_078.HTM

C++ Preprocessor – Tutorialspoint

tutorialspoint.com

https://www.tutorialspoint.com/cplusplus/cpp_preprocessor.htm

#ifdef – #ifndef – #elseif – #elif – #else – #endif

people.vcu.edutest1 is defined, test2 and test3 are unchecked test2 is defined If an #ifdef is evaluated to be false, then the #elseif directive is processed as if it was an #ifdef directive. If all #elseif directives evaluate to be false, the #else directive is processed if it exists. Input is evaluated until an #endif directive is …

http://www.people.vcu.edu/~jsiebers/mcnpinfo/dcomment/manual/node9.html

C/C++ Preprocessor directives | Set 2 – GeeksforGeeks

geeksforgeeks.org2017-07-08 · #ifdef: This directive is the simplest conditional directive. This block is called a conditional group. The controlled text will get included in the preprocessor output iff the macroname is defined. The controlled text inside a conditional will embrace preprocessing directives. They are executed only if the conditional succeeds. You can nest these in multiple layers, but they must be …

https://www.geeksforgeeks.org/cpp-preprocessor-directives-set-2/

What is difference between #if and #ifdef

interviewsansar.com2017-03-06 · This Preprocessor Directives #ifdef only checks if the symbol is defined or not and doesn’t care for its value. For example, symbol LOG_ENABLED has been defined here and has a value 0 or 1. #define LOG_ENABLED 0 // YES =1, NO=0

https://www.interviewsansar.com/difference-between-preprocessor-if-and-ifdef/

Arduino Preprocessor Directives Tutorial – ifdef & endif

deviceplus.com2017-06-06 · #ifdef macro_name //compile this code if macro_name exists #endif The above is a just shorthand for #if defined , which can be used to test multiple macros in a single condition. Note that every condition has to end with #endif directive, to specify which parts of the code are affected by the condition, and which ones are not.

https://www.deviceplus.com/arduino/arduino-preprocessor-directives-tutorial/

C++ Tutorial: 5.5, Preprocessor directives

people.scs.carleton.ca#define, #undef, #ifdef, #ifndef, #if, #endif, #else, #elif, #line, #error, #include and #pragma. Section 5.5 Preprocessor directives: Preprocessor directives are orders that we include within the code of our programs that are not instructions for the program itself but for the preprocessor. The preprocessor is executed automatically by the compiler when we compile a program in C++ and is in …

http://people.scs.carleton.ca/~dehne/projects/cpp-doc/tutorial/tut5-5.html

C/C++ Color Coding – support #ifdef condition for "Color …

community.slickedit.com2018-03-13 · Author Topic: C/C++ Color Coding – support #ifdef condition for "Color inactive code regions" (Read 1370 times) gfinlay. Community Member; Posts: 12; Hero Points: 1; C/C++ Color Coding – support #ifdef condition for "Color inactive code regions" « on: March 12, 2018, 09:30:05 pm » I’m currently using SE 22.0.2.1. I can get the C/C++ Color Coding feature for "Color inactive code …

https://community.slickedit.com/index.php?topic=16060.0

#ifdef 0 or #ifdef APP_DEBUG

social.msdn.microsoft.com2008-06-02 · Hi All, I have seen a lot of C++ codes have the following: #ifdef 0 <pirntf statement> #endif or #ifdef APP_DEBUG <pirntf statement> #endif Can you please explain when/how to make these printf statement inside the #ifdef executed. Thanks, JP · Change #ifdef 0 to #ifdef 1. Project + Properties, C/C++, Preprocessor, Preprocessor Definitions. Add APP_DEBUG.

https://social.msdn.microsoft.com/Forums/en-US/bfc62051-a9fb-442e-a0ce-02d58c16afaa/ifdef-0-or-ifdef-appdebug

[Solved] Shall I remove these #ifdef / #ifndef statements …

codeproject.com2020-11-05 · I am refactoring some legacy C++ code and see such statements from a resource.h header file: //{{NO_DEPENDENCIES}} // Microsoft Visual C++ generated include file. // Used by COMIntro.rc // #define IDS_HELLO 1 // Next default values for new objects // #ifdef APSTUDIO_INVOKED #ifndef APSTUDIO_READONLY_SYMBOLS #define _APS_NEXT_RESOURCE_VALUE 101 #define …

https://www.codeproject.com/Questions/5284528/Shall-I-remove-these-sharpifdef-sharpifndef-statem

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