I have exactly the same problem. I never had problems with eclipse before under linux and now it wont even compile code. I tried to change the name of the g++ and gcc compilers to their exact location in project->properties->c/c++ Build->discovery options etc. nothing helped, I tried to reinstall eclipse and did an initialize, added the path to the variables etc.. Nothing worked so fare. The project I am working on is quiet big and I rather would like eclipse to manage the source and makefile, instead of doing it manually

Linux Mint 15 Eclispe: Version: 3.8.1 (I tried it with the latest version as well ... nothing changed)

g++ --version g++ (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3 Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

gcc --version gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3 Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

example:

#include // not resolved using namespace std;

int main() {
    std::cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
    return 0;
}

Well the code above is not what bothers me, as I can fix it by adding the includes of the exact c++ include path, but the code just wont compile. Wired enough eclipse gives me the error:

Description Resource Path Location Type Program "g++" not found in PATH Preferences, C++/Build/Settings/Discovery, [CDT GCC Builtin Compiler Settings] options C/C++ Scanner Discovery Problem

but it appears to me to be possible to compile single files, by opening them and pressing crt+b, but the whole project wont compile.

Fixed the problem this morning:
- got the latest eclipse
- created a new workspace
- created a new project

after a few seconds the very same error disappears

I had similar problem and it is solved by

1. Installing g++ The GNU C++ complier using ubuntu software centre and

2. Changing in -

   Window -> Preferences -> C/C++ -> Build -> Settings -> Discovery -> CDT GCC Build in Complier Settings [Shared]

   From: ${COMMAND} -E -P -v -dD "${INPUTS}"

   To: /usr/bin/${COMMAND} -E -P -v -dD "${INPUTS}"

I hope it helps. I think if you add it to the project as mentioned in the first answer, you will need to add all the time for new projects. And if you add as I wrote you don't need to add it for new projects.

GCC: GNU Compiler Collection

• Referrers to all the different languages that are supported by the GNU compiler.

gcc: GNU C      Compiler
g++: GNU C++ Compiler

The main differences:

1. gcc will compile: *.c/*.cpp files as C and C++ respectively.
2. g++ will compile: *.c/*.cpp files but they will all be treated as C++ files.
3. Also if you use g++ to link the object files it automatically links in the std C++ libraries (gcc does not do this).
4. gcc compiling C files has less predefined macros.
5. gcc compiling *.cpp and g++ compiling *.c/*.cpp files has a few extra macros.

Extra Macros when compiling *.cpp files:

#define __GXX_WEAK__ 1
#define __cplusplus 1
#define __DEPRECATED 1
#define __GNUG__ 4
#define __EXCEPTIONS 1
#define __private_extern__ extern

For c++ you should use g++.

It's the same compiler (e.g. the GNU compiler collection). GCC or G++ just choose a different front-end with different default options.

In a nutshell: if you use g++ the frontend will tell the linker that you may want to link with the C++ standard libraries. The gcc frontend won't do that (also it could link with them if you pass the right command line options).

Although the gcc and g++ commands do very similar things, g++ is designed to be the command you'd invoke to compile a C++ program; it's intended to automatically do the right thing.

Behind the scenes, they're really the same program. As I understand, both decide whether to compile a program as C or as C++ based on the filename extension. Both are capable of linking against the C++ standard library, but only g++ does this by default. So if you have a program written in C++ that doesn't happen to need to link against the standard library, gcc will happen to do the right thing; but then, so would g++. So there's really no reason not to use g++ for general C++ development.

The only notable difference is that i you pass a .c to gcc it will compile as C, whereas g++ will always treat it as C++

“GCC” is a common shorthand term for the GNU Compiler Collection. This is both the most general name for the compiler, and the name used when the emphasis is on compiling C programs (as the abbreviation formerly stood for “GNU C Compiler”).

When referring to C++ compilation, it is usual to call the compiler “G++”. Since there is only one compiler, it is also accurate to call it “GCC” no matter what the language context; however, the term “G++” is more useful when the emphasis is on compiling C++ programs.

You could read more here: http://gcc.gnu.org/onlinedocs/gcc-3.3.5/gcc/G_002b_002b-and-GCC.html

gcc is the GNU C Compiler you should not use it to compile a C++ program, because it will give a linking error, that it can't link with the C++ standard library. g++, however, is the C++ frontend to gcc, and automatically links with the C++ standard library. GCC stands for the GNU Compiler Collection, which includes both the C and C++ compilers (gcc and g++), and some other ones, including Fortran and Java (gfortran and gcj).