What is a "translation unit" in C++?

C++

C++ Problem Overview

I am reading at the time the "Effective C++" written by Scott Meyers and came across the term "translation unit".

Could somebody please give me an explanation of:

  1. What exactly it is?

  2. When should I consider using it while programming with C++?

  3. Is it related to C++ only, or it can be used with other programming languages as well?

I might already use it without knowing the term...

C++ Solutions

Solution 1 - C++

From here: (wayback machine link)

> According to standard C++ (wayback machine link) : > A translation unit is the basic unit > of compilation in C++. It consists of > the contents of a single source file, > plus the contents of any header files > directly or indirectly included by it, > minus those lines that were ignored > using conditional preprocessing > statements. > > A single translation unit can be > compiled into an object file, library, > or executable program. > > The notion of a translation unit is > most often mentioned in the contexts > of the One Definition Rule, and > templates.

Solution 2 - C++

A translation unit is for all intents and purposes a file (.c/.cpp), after it's finished including all of the header files.

http://msdn.microsoft.com/en-us/library/bxss3ska%28VS.80%29.aspx

Solution 3 - C++

A hard question to answer definitively. The C++ standard states:

> The text of the program is kept in units called source files in this International Standard. A source file > together with all the headers (17.4.1.2) and source files included (16.2) via the > preprocessing directive #include, less any source lines skipped by any of the > conditional inclusion (16.1) > preprocessing directives, is called a translation unit. [Note: a C++ > program need not all be translated at > the same time. ]

So for most intents and purposes a translation unit is a single C++ source file and the header or other files it includes via the preprocessor #include mechanism.

Regarding your other questions:

> 2) When should I consider using it > when programming with C++

You can't not use it - translation units are the basis of a C++ program.

> 3) If it is related only to C++, or it > can be used with other programming > languages

Other languages have similar concepts, but their semantics will be subtly different. Most other languages don't use a preprocessor, for example.

Solution 4 - C++

The book makes it clear enough. When Meyers referes to a "translation Unit", he means a source code file.

Solution 5 - C++

A translation unit is code that is passed to the compiler proper. This typically means the output from running the preprocessor on the .c file.

Solution 6 - C++

In addition to the ODR, the translation unit is important in the definition of unnamed namespaces, which replaces one of the old uses of "static".

I guess I still don't have enough points to add a comment under the top answer.

Solution 7 - C++

C and C++ programs consist of one or more source files, each of which contains some of the text of the program. A source file, together with its include files (files that are included using the #include preprocessor directive) but not including sections of code removed by conditional-compilation directives such as #if, is called a "translation unit."

Solution 8 - C++

According to MSDN: C and C++ programs consist of one or more source files, each of which contains some of the text of the program. A source file, together with its include files (files that are included using the #include preprocessor directive) but not including sections of code removed by conditional-compilation directives such as #if, is called a "translation unit."

Solution 9 - C++

Every cpp/c (implementation) file will be converted into a translation unit (ie.,object file (.obj)) headers in the cpp file will be replaced with the actual text from the header files.

Solution 10 - C++

As others have said, a translation unit is basically the contents of a source file after preprocessing. It's the topmost production in the language grammar; you would only need to worry about it if you were writing a C or C++ compiler.

Solution 11 - C++

In my view, a "translation unit" is typically a single "post-preprocessing" source file. You can get more details on this MSDN page. http://msdn.microsoft.com/en-us/library/bxss3ska(v=vs.80).aspx

Categories
Recommended C++ Solutions

Previous Solution:

Batch file to copy files from one folder to another folder

Batch FileFile Io

Next Solution:

How to make the window full screen with Javascript (stretching all over the screen)

JavascriptFullscreen

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionHarryView Question on Stackoverflow
Solution 1 - C++JeffHView Answer on Stackoverflow
Solution 2 - C++Ana BettsView Answer on Stackoverflow
Solution 3 - C++anonView Answer on Stackoverflow
Solution 4 - C++Ed S.View Answer on Stackoverflow
Solution 5 - C++sigjuiceView Answer on Stackoverflow
Solution 6 - C++Allan StokesView Answer on Stackoverflow
Solution 7 - C++ganesh marmatView Answer on Stackoverflow
Solution 8 - C++rahulView Answer on Stackoverflow
Solution 9 - C++yesraajView Answer on Stackoverflow
Solution 10 - C++John BodeView Answer on Stackoverflow
Solution 11 - C++YangView Answer on Stackoverflow