g++ vs gcc

anandt4u · 06-02-2005, 04:02 PM

can someone give me the difference bet g++ and gcc??

itsme86 · 06-02-2005, 04:33 PM

g++ is a C++ compiler, gcc is a C compiler.

anandt4u · 06-02-2005, 04:42 PM

Quote:

Originally posted by itsme86
g++ is a C++ compiler, gcc is a C compiler.

what?? do you mean g++ was written in c++ and gcc in C???

both g++ and gcc compile c and c++ programs

aluser · 06-02-2005, 08:18 PM

On my machine, gcc doesn't like c++ programs correctly, at least with default arguments. Also, g++ will compile and link a c++ program which has a .c extension, while gcc won't even compile it. (looks like it doesn't know where the c++ headers are)

gcc and g++ do share a lot of code. In fact, I want to say that g++ just invokes gcc with some set of additional arguments.

jtshaw · 06-03-2005, 06:38 AM

g++ is just a wrapper for gcc.

gcc -Lstdc++ == g++

aluser · 06-03-2005, 09:03 AM

Code:

09:58 aluser@alf:~/test/c$ cat hello.cpp 
#include <iostream>

using namespace std;

int main() {
        cout << "hello world\n";
        return 0;
}
09:58 aluser@alf:~/test/c$ gcc -Lstdc++ -o hello hello.cpp
/tmp/cc4E4x2P.o(.text+0x1b): In function `main':
: undefined reference to `std::cout'
/tmp/cc4E4x2P.o(.text+0x20): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
/tmp/cc4E4x2P.o(.text+0x49): In function `__static_initialization_and_destruction_0(int, int)':
: undefined reference to `std::ios_base::Init::Init[in-charge]()'
/tmp/cc4E4x2P.o(.text+0x7a): In function `__tcf_0':
: undefined reference to `std::ios_base::Init::~Init [in-charge]()'
/tmp/cc4E4x2P.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status
09:58 aluser@alf:~/test/c$ g++ -o hello hello.cpp
09:59 aluser@alf:~/test/c$

This is on debian sarge. not quite sure what's going on, but the two aren't quite equivalent.

Even if we get the -L and -Is figured out, I'm fairly sure that g++ will compile c++ files with a .c extension, where gcc will give you a bunch of syntax errors.

Mostly the same code, but there are enough differences that you want to get in the habit of using the right one : )

jtshaw · 06-03-2005, 09:19 AM

Quote:

Mostly the same code, but there are enough differences that you want to get in the habit of using the right one : )

Technically speaking it is 100% the same source code. The difference is when you use a front end wrapper like g++ it assumes you are compiling c++ code regardless of the file extension you use. When you just invoke "gcc" it decides what language the source is in based on the extension of the file.

".c" are assumed to be C files.
".cxx", ".cc", ".cpp", ".C", ect. are assumed to be C++.

Check out the Compiling C++ section of the GCC manual for more info.

Quote:

g++ is a program that calls GCC with the default language set to C++, and automatically specifies linking against the C++ library. On many systems, g++ is also installed with the name c++.

- The GCC Manual.

anandt4u · 06-03-2005, 10:36 AM

thanks for all the info