Dimensional Data

C++ is a very decent programming language that has a very strong compiler supported by a big community on a range of different platforms. The C++ language definitions, syntax, and functionality are organized into different standards. Those standards are usually named after the year the standard was adopted such as 1998 for C++98, 2011 for4 C++11, 2014 for C++14, and 2017 for C++17. One of the great features of a C++ compiler is you can choose which standards you want your code to be compiled against, before the compilation of your source code. This allows the compiler to check that your code complies with that standard. In this post, we explain what the standards are, how you can view them, how you can check the compatibility of your C++ source code against different standards, and how you can choose to use C++ standards in C++ compiler options. What is a C++ standard? Standards are an international agreement for C++ compilers, made by the IDE and compiler developers of different operating systems (Embarcadero C++ Builder, Microsoft MSVC, GNU GCC, Apple Swift, etc.). They are formal, legal, and very high-level detailed technical documents intended primarily for people writing C++ compilers and standard library implementations.  The current available standards and some of their key features are listed below. How to use C++ standards in C++ compiler options? When we use ‘-std=’ option in a C++ compiler this option type enables or disables some features. We need to use these features to see the effect of each C++ standard option. Personally, I always prefer to use the latest version of the standards in my compilers. However, when programming, sometimes you may have to work on old or legacy C++ source, or you may be programming to another company that uses older standard compilers. Or maybe you just want to check if your code is compatible with a particular standard, or the code uses new standards. At these times, you can use std option in C++ compilers. In general, we can use the -std option to compile to a particular C++ standard. Here are some option examples, -std=c++98 -std=c++11 -std=c++14 -std=c++17 -std=c++20 or -std=c++2a For example, if you want to compile your code with C++11 features, you can use C++ Builder 64bits command line compiler as shown below: bcc64 –std=c++11 myapp.cpp –o myapp For an example, we can write this C++ code below which uses a feature found in the C++17 standard and above. int main() {   static_assert(sizeof(int)==4); // C++17 feature     return 0; } If you are using the C++17 compiler, this code will be compiled successfully because the static_assert feature comes with C++17. If you compile this code with -std=c++11 or -std=c++14 options this time you will get warning which is telling you that you have requested C++ standard version 11, but there is a feature that requires C++ standard version 17 (Until C++17, a message was required w/ static_assert). How to use C++ standards in the C++ Builder compiler options? In C++ Builder CLANG compiler, we can use -std option to compile in previous standards. This option can be used in bcc32c and bcc64, both support these std options below, -std=c++11 -std=c++14 -std=c++17 I should note that, C++11 and C++14 options are partially supported, these options do not have a STL that works with all, so you have the latest STL one for C++17. According […]

C++11 brings a lot of improvements and I think one of the most important features were the Unicode Character Types and Literals that allow more support for strings in different languages globally. C++11 introduced a new character type to manipulate Unicode character strings. This can be used in C++11, C++14, C++17, and above. This feature improved interactions in next generation C++ applications, like chat, social media applications, and so on by allowing a more diverse set of language characters and symbols to be displayed as well as emoticons. In this post, we explain what are Unicode character types and literals in Modern C++. What are Unicode character types and literals in Modern C++ 11? Unicode character types and literals allow more support for different languages, characters, and symbols in strings. C++11 introduces new character types to manipulate Unicode character strings. These can be used in C++11, C++14, C++17, and above. This feature improved language support in editor and design applications (i.e. RAD Studio uses Unicode Strings). It also vastly improved interactions in the next generation C++ applications like chat and social media. This is why we can display smiley faces ????, Vulcan hand signals ???? and love hearts ????. C++ Builder implements new character types and character literals for Unicode. These types are among the C++11 features added to bcc32, bcc32c, and bcc64 compilers. 1. New character types C++11 introduces new character types to manipulate Unicode character strings. For more information on this feature, see Unicode Character Types and Literals (C++11). 2. Unicode string literals C++11 introduces new character types to manipulate Unicode string literals. For more information on this feature, see Unicode Character Types and Literals (C++11). 3. Raw string literals 4. Universal character names in literals In order to make the C++ code less platform-dependent, C++11 lifts the prohibitions regarding control and basic source universal character names within character and string literals. Prohibitions against surrogate values in all universal character names are added. For more information on this feature, see Universal character names in literals Proposal document. 5. User-defined literals C++11 introduces new forms of literals using modified syntax and semantics in order to provide user-defined literals. Using user-defined literals, user-defined classes can provide new literal syntax. For more information on this feature, see User-defined literals Proposal document. What are the Unicode character types char16_t and char32_t in Modern C++? With the C++11 standards, two new types were introduced to represent Unicode characters: char16_t is a 16-bit character type. char16_t is a C++ keyword. This type can be used for UTF-16 characters. char32_t is a 32-bit character type. char32_t is a C++ keyword. This type can be used for UTF-32 characters. The existing wchar_t type is a type for a wide character in the execution wide-character set. A wchar_t wide-character literal begins with an uppercase L (such as L’c’). We have a very good post that explains how you can use character literals in modern C++. What are the character literals u’character’ and U’character’ in Modern C++? There are two new ways to create character literals of the new types: u’character’ is a literal for a single char16_t character, such as u’g’. A multicharacter literal such as u’kh’ is badly formed. The value of a char16_t literal is equal to its ISO 10646 code point value, provided that the code point is representable as a 16-bit value. Only characters in the basic multilingual plane (BMP) can be represented. U’character’ is a literal for a single char32_t character, such as U’t’. A multicharacter literal such as U’de’ is ill-formed. […]

C++11 brings a lot of improvements over C++98. In C++98, two consecutive right-angle brackets (>>) give an error, and these constructions are treated according to the C++11 standard which means CLANG compilers no longer generate an error about right angle brackets. In this post, we explain this and how to solve the right-angle bracket problem in C++. What is the right-angle bracket problem in C++? Ever since the introduction of angle brackets in C++98, C++ developers have been surprised by the fact that two consecutive right-angle brackets must be separated by whitespace. For example, if you declare two-dimensional vector (int and bool) as below: #include   typedef std::vector vec1;  // OK   typedef std::vector vec2;  // Error In C++98, the first declaration is OK, but the second declaration give errors because of ‘>>‘ (right angle brackets). However, both are OK in C++11 and above. One of the problems was an immediate consequence of the “maximum munch” principle and the fact that >> is a valid token (right shift) in C++. In the CLANG-enhanced C++ compilers, two consecutive right-angle brackets no longer generate an error, and these constructions are treated according to the C++11 standard. This issue was a minor issue in C++98, but persisting, annoying, and somewhat embarrassing problem. The cost was reasonable, and it seems therefore worthwhile to eliminate the surprise. C++98 developers needed to add space between them. If you want to get more information, you can see details here. How can I solve the right-angle bracket problem in C++? If you have C++98 compiler and come across the right-angle bracket problem, you need to add space between two ‘>’ right angle brackets. ‘>>’ should be written as ‘> >’ as shown in the example below. #include   typedef std::vector vec2;  // OK   int main() { } Or you should change your C++ compiler so that it supports C++11 or above. C++17 is recommended. Note that the latest RAD Studio, C++ Builder standard and CLANG compilers supports C++17 features. What is the right-angle bracket support in C++ 11? In the Clang-enhanced C++ compilers, two consecutive right-angle brackets no longer generate an error, and these constructions are treated according to the C++11 standard.This example below with ‘>>’ right angle brackets can be successfully compiled with any compiler that supports C++11 and above. #include   typedef std::vector vec1;  // OK C++11 and above   int main() { } For more information, see the C++11 proposal document at Right Angle Brackets Proposal document