conditional-compilation

In a Swift project before I've been able to perform a simple compiler check to see which scheme is running, then conditionally include code or not. For example: #if MyScheme Add code here #endif But for some reason, in my Objective-C project, this doesn't seem to be working. Should this work the same way? Or does the Swift compiler have some advancements which allow this kind of behaviour? Use #ifdef //example for debug scheme #ifdef NDEBUG Add code here #endif And you can define your preprocessor macros here Hope this helps 来源： https://stackoverflow.com/questions/45659435/conditional

I would like to write a cross-platform function in C++ that contains system calls. What conditional compilation flags can I check to determine which operating system the code is being compiled for? I'm interested mostly in Windows and Linux, using Visual Studio and GCC. I think it should look something like this: void SomeClass::SomeFunction() { // Other code #ifdef LINUX LinuxSystemCall(); #endif #ifdef WINDOWS WindowsSystemCall(); #endif // Other code } My gcc (4.3.3) defines the following Linux-related predefined macros: $ gcc -dM -E - < /dev/null | grep -i linux #define __linux 1 #define _

I have some C++ code, and want to perform an action if the __APPLE__ or __linux macros are defined. If I did it as a normal if conditional, it would be easy using || : if (something || something) { .. code .. } But as of what I know there is no || operator for #ifdef statements. How would I check if __APPLE__ or __linux is defined using a single #ifdef statement? You can't in a single #ifdef would a single #if do instead? #if defined(__APPLE__) || defined(__linux) this also works if you prefer #if defined __APPLE__ || defined __linux In my C++ there is. #if defined(__APPLE__) || defined(_

I'm currently working on a VBA code generator/injector that adds VBA functionality to Excel workbooks by using the VBA Extensibility. This all works fine. However, the original code that is injected uses conditional compilation, referring to some global conditional compilation arguments: Is there any way I can programmatically modify/add the conditional compilation arguments of a VBA project? I checked all properties of the VBProject but couldn't find anything. Peter Albert Inspired by this approach , shown by SiddharthRout, I managed to find the following solution using SendMessage and

I would like to edit a single rmarkdown (Rmd) document with a list of "problems", each followed by its solution. Each solution may contain the results of R console, but also some explaining (markdown and LaTeX formatted) text. Besides, I would like to knitr it in 2 versions: with and without the solutions, changing the source as less as possible, and compiling. I know I can use a logical variable in order to conditionally evaluate R code and show plots and R output, but I don't know how to show/hide blocks of (markdown and LaTeX) formatted text, unless I put all that text into R character

I am fairly new to C++. I am currently working on a group project and we want to make our classes compatible with both the lab computers (Windows) and my computer (Mac OS X). Here is what we have been putting at the top of our files: #ifdef TARGET_OS_X # include <GLUT/glut.h> # include <OpenGL/OpenGL.h> #elif defined _WIN32 || defined _WIN64 # include <GL\glut.h> #endif I realize this question has been asked before but my searches have been giving me conflicting answers such as "_MAC", "TARGET_MAC_OS", "MACINTOSH", etc. What is the current and correct declaration to put in the #ifdef statement

In C++, is this: #ifdef A && B the same as: #if defined(A) && defined(B) ? I was thinking it wasn't, but I haven't been able to find a difference with my compiler (VS2005). They are not the same. The first one doesn't work (I tested in gcc 4.4.1). Error message was: test.cc:1:15: warning: extra tokens at end of #ifdef directive If you want to check if multiple things are defined, use the second one. Svetlozar Angelov Conditional Compilation You can use the defined operator in the #if directive to use expressions that evaluate to 0 or 1 within a preprocessor line. This saves you from using