This very simple C++ program using the standard library doesn't compile with GCC

Question

I can't figure out why this isn't working...

I am working in Linux.

g++ doesn't do anything.

gcc prints the following:

/tmp/ccyg7NDd.o: In function `main':
test.cc:(.text+0x14): undefined reference to `std::cout'
test.cc:(.text+0x19): 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*)'
test.cc:(.text+0x21): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)'
test.cc:(.text+0x29): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))'
/tmp/ccyg7NDd.o: In function `__static_initialization_and_destruction_0(int, int)':
test.cc:(.text+0x51): undefined reference to `std::ios_base::Init::Init()'
test.cc:(.text+0x56): undefined reference to `std::ios_base::Init::~Init()'
/tmp/ccyg7NDd.o:(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

Code:

#include <iostream>
#include <stdio.h>

int main(){

    std::cout << "test " << std::endl;
    return 0;
};

`gcc` is the C compiler, you need to use `g++`. What do you mean `g++` does not do anything? You have to execute the compiled binary after you build it (i.e. when `g++` completes). — hmjd, Feb 25 '12 at 19:46
@hmjd: g++ **is** gcc, it just automatically links against libstdc++. You can get the same effect with gcc by supplying `-lstdc++`. — Oliver Charlesworth, Feb 25 '12 at 19:48
What @hmjd said: after running `g++` you want to run the file which, with no other options, is called `a.out`. — smparkes, Feb 25 '12 at 19:49
by it doesn't do anything I mean it doesn't print to the console...which i think it should — spatara, Feb 25 '12 at 19:56
@spatara: The compiler will only print something if there's a problem. Like most Unix-style programs, silence means success. You should find a program called `a.out`, or something else if you gave a `-o` option to the compiler; running that should print `test ` to the console. — Mike Seymour, Feb 25 '12 at 20:12
@spatara If you don't like the silence, you can pass the `--verbose` flag and it'll tell you more than you want to know. — Daniel Fischer, Feb 25 '12 at 20:41
g++ dosen't do anything? Look at the new file in the folder. Not doing anything is compilation success! — ihsoy ih, Dec 20 '12 at 15:10

score 86 · Accepted Answer · edited May 08 '22 at 11:36

86

g++ main.cpp

or

gcc main.cpp -lstdc++

edited May 08 '22 at 11:36

HolyBlackCat

78,603
9
131
207

answered Feb 25 '12 at 19:47

kev

155,172
47
273
272

score 22 · Answer 2 · edited May 08 '22 at 11:32

gcc is the C compiler. You need to use g++ (or use gcc with option -lstdc++ as pointed out by others). If by nothing is printed after you use g++ is what you mean, you have to execute the compiled binary after you build it (i.e., when g++ completes).

main.cpp:

#include <iostream>

int main(){

    std::cout<<"test "<<std::endl;
    return 0;
};

Build:

g++ main.cpp -o main

Execute:

./main

Output:

test

score 5 · Answer 3 · edited May 08 '22 at 11:30

5

This is C++ code and so you should use executable g++ and not executable gcc.

Also, #include<stdio.h>, is not needed.

edited May 08 '22 at 11:30

Peter Mortensen

30,738
21
105
131

answered Feb 25 '12 at 19:48

bisarch

1,388
15
31

score 2 · Answer 4 · answered Feb 25 '12 at 19:48

2

I think you are mistakenly linking with the C compiler command instead of the C++ compiler command. Try this:

g++ test.cc -o test

answered Feb 25 '12 at 19:48

Thomas Padron-McCarthy

27,232
8
51
75

score -1 · Answer 5 · edited May 08 '22 at 11:37

-1

I think the underlying issue for this is that the binary name "test" is actually already apart of the Linux system. Typing in "man test" displays a manual for the test binary. I had the exact same issue. It was resolved simply by compiling the binary to something other than "test".

edited May 08 '22 at 11:37

Peter Mortensen

30,738
21
105
131

answered Aug 28 '14 at 23:33

jjdaybr

9

But the ***real*** issue was that "`test`" was used instead of "`./test`"(?). The canonical question is *[How can I compile and run C/C++ code in a Unix console or Mac terminal?](https://stackoverflow.com/questions/221185/)*. – Peter Mortensen May 08 '22 at 13:52

This very simple C++ program using the standard library doesn't compile with GCC

5 Answers5

Linked

Related