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- Dictionaryopt/ɒpt/
verb
- 1. make a choice from a range of possibilities: "consumers will opt for low-priced goods"
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This is part of Microsoft's Source-Code Annotation Language. _In_Opt_ means you may pass NULL. Thank you very much. Now that I have a name for these annotations (I originally thought that they were interpreted and meant something significant to the compiler), I have a starting point for further research.
Nov 21, 2010 · #define __in #define __out #define __in_opt Meaning they get replaced with nothing on the Preprocessor pass. Are they just a documentation method, without any functionality? If so, I can see the advantage to documenting the code in line like this. With something like doxygen you need to write out the parameter names twice.
Jul 5, 2017 · When you build the project with /analyze compiler option (Project Properties, Code Analysis -> General), these play important role in finding the coding issues. For example, if a particular pointer argument says __in then it must not be passed a null pointer. The function will not check for null and may cause SEH. __in_opt argument may be null.
Jul 4, 2018 · 4. The answer is yes! To the extent that you could already have recursive macros in C, you can do it in C++20 and __VA_OPT__ makes some things way, way nicer. Here's an example (with explanation) of what you can do: define a FOR_EACH macro that applies a macro to a bunch of arguments and is way nicer than the horrible things you had to do prior ...
Jul 22, 2021 · PP_THIRD_ARG(__VA_OPT__(,),true,false,) #define VA_OPT_SUPPORTED VA_OPT_SUPPORTED_I(?) static_assert(VA_OPT_SUPPORTED); gcc and clang pass it; the MSVC version does not. I then looked at clang's warnings; it is a warning that tells you if you pass 0 arguments to ... .
Oct 26, 2013 · So if you enter a non-optional argument after the option, it prints the argument. But I want it to print out the char "string" if the user doesn't supply a non-optional argument (this is why I put the double colon in the OPT_LIST). But I'm not sure how to do this so any help would be greatly appreciated. Heres what happens when I run the program:
Feb 21, 2014 · alt is used to describe alternative scenarios of a workflow. Only one of the options will be executed. opt is used to describe an optional step in the workflow. For example, for an online shop purchase sequence diagram you may use opt to describe how the user can add gift wrapping if she wishes. alt may be used to describe two variants of ...
38. In C++20, the preprocessor supports __VA_OPT__ as a way to optionally expand tokens in a variadic macro if the number of arguments is greater than zero. (This obviates the need for the ##__VA_ARGS__ GCC extension, which is a non-portable and ugly hack.) Clang SVN has implemented this feature, but they haven't added a feature test macro for ...
Dec 21, 2023 · 1. Unfortunately __VA_OPT__ support in MSVC is broken in some versions of Visual Studio. I tested this with Microsoft Visual Studio 2022, version 17.8.3. Because __VA_OPT__ is a C++20 feature you will need to specify std:c++20 or later, but on my system that does not help. However if you use /Zc:preprocessor it does have some effect.
Just use the *args parameter, which allows you to pass as many arguments as you want after your a,b,c. You would have to add some logic to map args -> c,d,e,f but its a "way" of overloading. def myfunc(a,b, *args, **kwargs): for ar in args: print ar. myfunc(a,b,c,d,e,f) And it will print values of c,d,e,f.
