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In Ubuntu 12.04 LTS I installed the Eclipse CDT plugin and opened the new hello world project to just test everything out. When I was creating the project, I chose the only toolchain: "Linux GCC"

When the project is created, however, it says that


are unresolved. Thus, lines with cout and endl can't be used and it cannot find std.

using namespace std; is also causing problems.

How can I get my #include directives for standard library headers recognized, to support code using the std namespace?

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Do these errors persist even after you do Project > Build All? – Eliah Kagan Jun 14 '12 at 16:00
Mayne this is a stupid question but did you create a new project specifically as a C++ project rather than a C project? – bazz Jul 26 '12 at 21:42

If you had the same issue I did, I suspect that your project builds but code-completion / code highlighting fails? I've just found some notes that may be useful. Here's what I did:

  • Project->Properties

  • C/C++ General

  • Paths and Symbols

  • select the appropriate language

  • Click "Add" and add the compiler-version specific directories

For language 'GNU C++' I added:


For "GNU C" I added:


TBH, I don't think all the directories above are actually required (you could probably remove the 'bits' directories) but the list above worked for me at the time.

I am now using Eclipse Indigo (version 3.7.2) from and it automatically finds and adds the correct include directories. The list is different for me:


Clearly, only add the include directories that actually exist on your system ;-)

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Well, this doesn't work for me - although I'm actually on Debian Stretch 64-bit. But I did adapt your suggestions to my platform. – einpoklum Dec 11 '15 at 18:38

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