CODEWITHSUNDEEP
c++windowsmacos
avon_verma
avon_verma

Reputation: 1249

are programs coded separately for different operating systems?

If a program was written in c++ to run on Windows, does it have to be completely rewritten to run on Mac OS or a mobile OS?

Upvotes: 5

Views: 2974

Answers (5)

Charles Salvia
Charles Salvia

Reputation: 53289

This depends. In general, Standard C++ is a general-purpose, portable language which can be compiled to run on any system or platform that has a standard-compliant compiler.

However, a lot of the more "interesting" features you might want to add to a typical application are not part of Standard C++. This includes GUIs, threads, sockets, and low-level OS API calls. These are generally not portable, and parts of the code which use these features will need to be implemented separately for each operating system or platform.

Fortunately, this is not as daunting as it sounds, because there are a lot of cross-platform libraries in existence that have already gone through the trouble of doing this. For example, the Boost threading library already has threading code written for different platforms or operating systems, but all of this is abstracted behind a nice uniform API that can be used portably in C++ application code.

Additionally, a lot of non-Standard C++ code still conforms to some standard, such as POSIX, which is supported across multiple platforms. For example, most UNIX-ish systems, including Linux and Mac OS X, support POSIX threads (the pthread API).

Upvotes: 3

chrisaycock
chrisaycock

Reputation: 37930

Software can be written in multiple languages and then linked together. For example, I can code the back-end logic of my application in C++ (often using Boost), and then build two separate front-ends in C# for Windows and Objective-C for Mac. I can link the C++ and C# components to ship for one platform, then link the C++ and Objective-C components to ship for another. That approach will give the most "native" look-and-feel for each platform.

As alternative, I can code the entire front-end in C++ using Qt or WxWidgets. This will run on all platforms, albeit without 100% of a platform's bells and whistles.

Upvotes: 1

karlphillip
karlphillip

Reputation: 93410

If the code itself uses libraries that are supported on all the target platforms then you will only need the appropriate compilers to generate a valid binary for each system.

Upvotes: 1

templatetypedef
templatetypedef

Reputation: 372794

Typically, yes, because the program will need to use OS-specific features for windowing and possibly for other features as well (networking, synchronization, etc.) However, many programs try to mitigate this as much as possible by building wrapper classes so that most of the program deals with these wrappers rather than the raw platform-specific tools. To port the program from one platform to another, you just need to reimplement the wrappers using the new platform's tools.

Many programs take this a step further by using prewritten libraries like Qt or Boost to handle some of the cross-platform silliness, but this is (essentially) the above idea at a larger scale.

Upvotes: 4

Khaled Alshaya
Khaled Alshaya

Reputation: 96869

C++ is a standard language, which means that the source code that you write can be compiled on any platform which has an implementation of the C++ standard. There are two ways you can write C++ programs that can't be compiled on different implementation. First, if you use language extensions that are found on a specific (set of)implementation(s) only. Second, using a library that depends on code that doesn't ship with the standard library(like on OS API).

For the first matter, try always to write standard code. For the second, use cross-platform libraries like Boost, Qt...

Upvotes: 6

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