predefined-macro

问题 The directive: #ifndef __cplusplus #error C++ is required #elif __cplusplus < 201402L #error C++14 is required #endif The command-line: g++ -Wall -Wextra -std=c++14 -c -o header.o header.hpp My g++ version: g++ (tdm-1) 4.9.2 The error C++14 is required is generated even when I added -std=c++14 , I don't know why. Please tell me how to fix this. 回答1: According to the GCC CPP manual (version 4.9.2 and 5.1.0): __cplusplus This macro is defined when the C++ compiler is in use. You can use _

问题 The directive: #ifndef __cplusplus #error C++ is required #elif __cplusplus < 201402L #error C++14 is required #endif The command-line: g++ -Wall -Wextra -std=c++14 -c -o header.o header.hpp My g++ version: g++ (tdm-1) 4.9.2 The error C++14 is required is generated even when I added -std=c++14 , I don't know why. Please tell me how to fix this. 回答1: According to the GCC CPP manual (version 4.9.2 and 5.1.0): __cplusplus This macro is defined when the C++ compiler is in use. You can use _

问题 The directive: #ifndef __cplusplus #error C++ is required #elif __cplusplus < 201402L #error C++14 is required #endif The command-line: g++ -Wall -Wextra -std=c++14 -c -o header.o header.hpp My g++ version: g++ (tdm-1) 4.9.2 The error C++14 is required is generated even when I added -std=c++14 , I don't know why. Please tell me how to fix this. 回答1: According to the GCC CPP manual (version 4.9.2 and 5.1.0): __cplusplus This macro is defined when the C++ compiler is in use. You can use _

问题 In order to add 'todo' items into my code, I want to put a message in the compiler output. I would like it to look like this: c:/temp/main.cpp(104): TODO - add code to implement this in order to make use of the Visual Studio build output functionality to navigate to the respective line by double-clicking it. But the __LINE__ macro seems to expand to an int , which disallows writing #pragma message( __FILE__ "("__LINE__"): ..." ) Would there be another way? 回答1: Here is one that allows you to

问题 In earlier versions of Visual Studio, there was a predefinied macro "_CPPLIB_VER" which reported the version of the Dinkumware STL Library shipped with this version of VS. As of 2012, I am unable to find or use this macro - it is undefinied and I am unable to find any information on this matter online. Is the Dinkumware STL Lib no longer used in VS2012? Was the macro renamed? Windows 7 x64 Microsoft Visual Studio 2012 Professional 回答1: Usually the definition of _CPPLIB_VER can be found in a

问题 Is there a way to set some predefined Macros for my local installation of Code::Blocks. To elaborate on that, basically I would like to have certain blocks compiled only at pc and not anyplace I send the code to. One way to achieve this is as follows: #define MYPC #ifdef MYPC //do something #else // do something else #endif I was to achieve the same thing, but I don't want to include the line #define MYPC and woud like to add this somewhere in the IDE. I know how to do this in Visual Studio,

问题 I have a c++ project that has to print a revision string. The revision string is company wise specified and the protocol includes the build time as yyyy/mm/dd. I use to specify this as macro from the build system, but this is no longer an option because messes up the precompiled headers (in incremental build when the day changes). I am trying to implement this with obtaining the build date from the compiler but __DATE__ and __TIMESTAMP__ give the month in Mmm. Any ideas how I can take the

问题 I often find myself writing something like int computedValue = ...; return MAX(0, MIN(5, computedValue)); I would like to be able to write this as a single one-line macro. It must be free of side effects, in the same way that the existing system macros MIN and MAX are, and should work for the same data types as MIN and MAX. Can anyone show me how to turn this into a single macro? 回答1: This is without side effects and works for any primitive number: #define MIN(A,B) ({ __typeof__(A) __a = (A);

问题 I need the file name only where the __FILE__ and __FILEW__ macros return the whole path. I defined the following: #define __FILE_NAME_ONLY__ (strrchr(__FILE__, '\\') ? strrchr(__FILE__, '\\') + 1 : __FILE__) I am using it as follows: #define MY_TRACE( mask, format, ... ) \ GlobalTrace( mask, L"-[" __FILE_NAME_ONLY__ L":" format , __VA_ARGS__ ) I get the following error: error C2064: term does not evaluate to a function taking 1 arguments and when I try the following macros: #define __WIDE(

问题 I have googled for a list of predefined macros per architecture used by gcc without success. Is there such a list or do I need to -dM for crosscompilers. 来源： https://stackoverflow.com/questions/15860850/gcc-predefined-macros-for-architecture-x