什么是纯C++

Question

What does pure C++ mean? Please explain the different versions of C++ like Visual C++ and GNU C++.

How about compilers for these types of C++?

Answer 1

Pure C++ means C++ as per the ISO standard, with none of the vendor-specific extensions being used.

That means it should be portable across all implementations that support the standard. Otherwise you may find yourself locked in to a specific vendor, not necessarily a bad thing, but you should understand the implications of that decision.

Answer 2

Pure C++ is the form of C++ which only uses semantics defined by the ISO C++ standard.
The code implemented in Pure C++ is fully portable accross all Standard compilant C++ compilers.

Implementations are allowed to provide their own extensions over the features provided by the C++ standard. Each compiler provides so in the form of compiler extensions.

Thus,

Pure C++ = Features provided by Standard C++
Visual C++ = Features provided by Standard C++ + MSVC compiler extensions.
GNU C++ = Features provided by Standard C++ + GNU compiler extensions.

Answer 3

There is no such thing as "Pure C++". Either it's C++ or it's not. There are some companies that have made extensions to C++, that have new keywords like "WinMain", which are not part of the C++ standard. Perhaps that's what you're referring to.

Answer 4

Stanley Lipman describes the terminology Microsoft invented for their C++/CLI hybrid at http://msdn.microsoft.com/en-us/magazine/cc163852.aspx :

C++/CLI represents an integration of the Kansas and Oz of native and managed programming. In this iteration, that has been done through a kind of separate but equal community of source-level and binary elements, including Mixed mode (source-level mix of native and CTS types, plus a binary mix of native and CIL object files), Pure mode (source-level mix of native and CTS types, all compiled to CIL object files), Native classes (can hold CTS types through a special wrapper class only), and CTS classes (can hold native types only as pointers).

So, "Pure" C++ in a Microsoft world is a term for a specific blend of proprietary features and ISO Standard C++ features .

Stanley's description differentiates it from "Native" - which matches what other existing answers to this question describe as "pure". In the general English usage of the word, of course "pure" would be "native" = ISO Standard. Ostensibly, Microsoft picked a blatantly misleading term, such that people following tutorials/references on "Pure C++" may be unknowingly locking themselves and their code into use of proprietary Microsoft extensions, and therefore frustrated in any later attempts to port them to other Operating Systems.

terms C++ like Visual C++ and GNU C++. How about compilers for these types of C++.

Visual C++ is Microsoft's brand name for their C++ and C++/CLI compiler. GNU is an organisation that produces myriad open-source software products including GCC - the GNU Compiler Collection, which includes a C++ compiler.