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What is the difference between g++ and gcc?

c++ g++ gcc

Question

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

1
790
8/28/2018 12:46:01 AM

Accepted Answer

gcc and g++ are compiler-drivers of the GNU Compiler Collection (which was once upon a time just the GNU C Compiler).

Even though they automatically determine which backends (cc1 cc1plus ...) to call depending on the file-type, unless overridden with -x language, they have some differences.

The probably most important difference in their defaults is which libraries they link against automatically.

According to GCC's online documentation link options and how g++ is invoked, g++ is equivalent to gcc -xc++ -lstdc++ -shared-libgcc (the 1st is a compiler option, the 2nd two are linker options). This can be checked by running both with the -v option (it displays the backend toolchain commands being run).

665
10/9/2018 3:56:53 PM

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
Martin York

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