What is the difference between g++ and gcc?

Question

What is the difference between g++ and gcc? Which one of them should be used for general c++ development?

Answer 1

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 fewer 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

Answer 2

“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.

Answer 3

What is the difference between g++ and gcc?

gcc has evolved from a single language "GNU C Compiler" to be a multi-language "GNU Compiler Collection". The term "GNU C Compiler" is still used sometimes in the context of C programming.

The g++ is the C++ compiler for the GNU Compiler Collection. Like gnat is the Ada compiler for gcc. see Using the GNU Compiler Collection (GCC)

For example, the Ubuntu 16.04 and 18.04 man g++ command returns the GCC(1) manual page.

The Ubuntu 16.04 and 18.04 man gcc states that ...

g++ accepts mostly the same options as gcc

and that the default ...

... use of gcc does not add the C++ library. g++ is a program that calls GCC and automatically specifies linking against the C++ library. It treats .c, .h and .i files as C++ source files instead of C source files unless -x is used. This program is also useful when precompiling a C header file with a .h extension for use in C++ compilations.

Search the gcc man pages for more details on the option variances between gcc and g++.

Which one should be used for general c++ development?

Technically, either gcc or g++ can be used for general C++ development with applicable option settings. However, the g++ default behavior is naturally aligned to a C++ development.

The Ubuntu 18.04 'gcc' man page added, and Ubuntu 20.04 continues to have, the following paragraph:

The usual way to run GCC is to run the executable called gcc, or machine-gcc when cross-compiling, or machine-gcc-version to run a specific version of GCC. When you compile C++ programs, you should invoke GCC as g++ instead.

Answer 4

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).