I'm trying to do some really simple stuff in C++, but I can't find any information on how to tackle this. Even the book I have just says "Just compile and run the program".
test.cpp
#include <iostream>
using namespace std;
int main()
{
cout << "Never fear, C++ is here!";
return 0;
}
The compiler says:
Undefined symbols for architecture x86_64:
"std::cout", referenced from:
_main in ccVfJHGs.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in ccVfJHGs.o
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in ccVfJHGs.o
"std::ios_base::Init::~Init()", referenced from:
___tcf_0 in ccVfJHGs.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
I tried compiling with flags like -arch i386 and -m32 but it always says it's the wrong architecture. Which one should I use?
I'm doing this on a Mac but not using XCode, just gcc.
The error isn't that it's the wrong architecture, it's that std::cout (and other symbols) isn't defined.
You should compile and link with g++ not gcc, to automatically link with correct C++ libraries.
The error is caused because you're compiling with gcc, which only default-links libc.
You need to compile with g++ so that libstdc++ is auto-linked in too.
Use g++ instead of gcc to link with exact c++ libraries
Related
$clang++ main.cpp -o out
Got following error, the same error happens when changing to g++. I have tested on some simple simple c++ code, the command works fine. So it the problem in that PNG class file? However, the same files worked on my MacOS before, but suddenly failed today.
Undefined symbols for architecture x86_64:
"PNG::writeToFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main-f6a06a.o
"PNG::PNG(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main-f6a06a.o
"PNG::PNG(unsigned long, unsigned long)", referenced from:
_main in main-f6a06a.o
"PNG::~PNG()", referenced from:
_main in main-f6a06a.o
"PNG::operator()(unsigned long, unsigned long)", referenced from:
_main in main-f6a06a.o
"PNG::width() const", referenced from:
_main in main-f6a06a.o
"PNG::height() const", referenced from:
_main in main-f6a06a.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Did you miss providing static/shared to the linker to resolve the linker errors for the methods mentioned? Also note that clang++ is a different compiler compared to g++ and hence need the static/shared libraries compiled prior by the same compiler you are using (clang++).
Try:
clang++ main.cpp -o out -lpng
Here's why: You are not providing the library that contains the implementation of your PNG library (libpng most likely). You need -lpng added to your compiler, so that it links with the relevant library. It may not be exactly -lpng in your particular case, but it's definitely a "missing library". Without knowing exactly what library you are trying to use (you didn't provide some source to "try the fix with").
As pointed out in the comment: you are using some kind of C++ wrapper on top, the above is probably not enough - but without knowing exactly which C++ wrapper on the png functionality you are actually using, it's hard to say what the command-line should look like.
Perhaps this
I try to compile this cpp code on osx lion but I get an error.
#include <iostream>
using namespace std;
int main (int argc, char *argv[])
{
for(int i = 0; i < 10; i++)
{
cout << "hi";
cout << endl;
}
return 0;
}
To compile:
cc main.cpp
Error:
Undefined symbols for architecture x86_64:
"std::cout", referenced from:
_main in ccBdbc76.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in ccBdbc76.o
"std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
_main in ccBdbc76.o
"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> >&))", referenced from:
_main in ccBdbc76.o
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in ccBdbc76.o
"std::ios_base::Init::~Init()", referenced from:
___tcf_0 in ccBdbc76.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
Normally this sort of failure happens when compiling your C++ code by invoking the C front-end. The gcc you execute understands and compiles the file as C++, but doesn't link it with the C++ libraries. Example:
$ gcc example.cpp
Undefined symbols for architecture x86_64:
"std::cout", referenced from:
_main in ccLTUBHJ.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in ccLTUBHJ.o
"std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
_main in ccLTUBHJ.o
"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> >&))", referenced from:
_main in ccLTUBHJ.o
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in ccLTUBHJ.o
"std::ios_base::Init::~Init()", referenced from:
___tcf_0 in ccLTUBHJ.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
$ g++ example.cpp
$
As you can see, using g++ makes the problems go away. The same behaviour (with slightly different messages) occurs if you use clang (which I'd recommend):
$ clang example.cpp
Undefined symbols for architecture x86_64:
"std::ios_base::Init::~Init()", referenced from:
___cxx_global_var_init in cc-IeV9O1.o
"std::ios_base::Init::Init()", referenced from:
___cxx_global_var_init in cc-IeV9O1.o
"std::cout", referenced from:
_main in cc-IeV9O1.o
"std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
_main in cc-IeV9O1.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in cc-IeV9O1.o
"std::ostream::operator<<(std::ostream& (*)(std::ostream&))", referenced from:
_main in cc-IeV9O1.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
$ clang++ example.cpp
$
As you can see in the clang error message, you could use -v to see the linker invocation to see what's going wrong. It would show you this link line:
"/usr/bin/ld" -demangle -dynamic -arch x86_64
-macosx_version_min 10.6.8 -o a.out -lcrt1.10.6.o
/var/folders/zl/zlZcj24WHvenScwjPFFFQE+++TI/-Tmp-/cc-hdOL8Z.o
-lSystem /Developer/usr/bin/../lib/clang/3.0/lib/darwin/libclang_rt.osx.a
Or something like it - as you can see, it's linking the C runtime, not C++, and also doesn't have the C++ libraries. Using clang++ the link line is:
"/usr/bin/ld" -demangle -dynamic -arch x86_64
-macosx_version_min 10.6.8 -o a.out -lcrt1.10.6.o
/var/folders/zl/zlZcj24WHvenScwjPFFFQE+++TI/-Tmp-/cc-wJwxjP.o
/usr/lib/libstdc++.6.dylib -lSystem
/Developer/usr/bin/../lib/clang/3.0/lib/darwin/libclang_rt.osx.a
As you can see, libstdc++ is included, and presto - no link errors.
Try
g++ main.cpp
This way it should work, at least using OS X
I'm not familiar with OSX LION. However, in the strictest sense, the errors described are not caused by the compiler, but by the linker. It seems as if the standard library is not being linked.
Use CC command (uppercase) to compile C++ and link to standard C++ library.
As of Yosemite (10.10.1), I've found that gcc with the -lc++ flag also works:
gcc -lc++ main.cpp
If using clang on OS X , try :
clang++ simple_cpp_program_file.cpp -o simple_cpp_program_file.out
Here's the solution that works on macOs Sierra:
There are two implementations of the standard C++ library available on OS X: libstdc++ and libc++. They are not binary compatible and libMLi3 requires libstdc++.
On 10.8 and earlier libstdc++ is chosen by default, on 10.9 libc++ is chosen by default. To ensure compatibility with libMLi3, we need to choose libstdc++ manually.
To do this, add -stdlib=libstdc++ to the linking command.
Is this GCC on Windows (MinGW) or Linux? On MinGW you need the parameters -lmingw32 -enable-auto-import. Linux might needs something similar, -enable-auto-import is most likely needed.
So the error ld: library not found for -lstdc++ is where the actual error lies.
To fix this, open the folder
open /Library/Developer/CommandLineTools/Packages/
Run the package macOS_SDK_headers_for_macOS_10.14.pkg
Then gem install mini_racer works!
This issue may not be only related to mini_racer as it could affect any gem that compiles an extension.。
I'm trying to compile the Sam Hare's Struck code.
I'm using mac OSX10.9, opencv 2.4.6 and Eigen 2.0.17.
Eigen and opencv headers are stored in /opt/local/include while opencv dylib in /opt/local/lib.
I modified the Hare's Makefile to work on this folder. When I type make on the terminal:
g++ -L/opt/local/lib -lopencv_core -lopencv_highgui -lopencv_imgproc src/Config.o src/Features.o src/HaarFeature.o src/HaarFeatures.o src/HistogramFeatures.o src/ImageRep.o src/LaRank.o src/MultiFeatures.o src/RawFeatures.o src/Sampler.o src/Tracker.o src/main.o src/GraphUtils/GraphUtils.o -o struck
I get these errors:
Undefined symbols for architecture x86_64:
"cv::namedWindow(std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> > const&,
int)", referenced from:
_main in main.o "cv::split(cv::Mat const&, std::__1::vector<cv::Mat, std::__1::allocator<cv::Mat> >&)",
referenced from:
ImageRep::ImageRep(cv::Mat const&, bool, bool, bool) in ImageRep.o "cv::imread(std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> > const&,
int)", referenced from:
_main in main.o "cv::imshow(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&,
cv::_InputArray const&)", referenced from:
LaRank::Debug() in LaRank.o
Tracker::Debug() in Tracker.o
_main in main.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see
invocation)
Any ideas? Thanks!
I had a similar warning/error/failure when I was simply trying to make an executable from two different object files (main.o and add.o). I was using the command:
gcc -o exec main.o add.o
But my program is a C++ program. Using the g++ compiler solved my issue:
g++ -o exec main.o add.o
I was always under the impression that gcc could figure these things out on its own. Apparently not. I hope this helps someone else searching for this error.
finally solved my problem.
I created a new project in XCode with the sources and changed the C++ Standard Library from the default libc++ to libstdc++ as in this and this.
I am getting the same error. I don't think it is a "fix", but my work-around is to also include the cpp file. So instead of just putting
#include "MyClass.h"
I have to put
#include "MyClass.h"
#include "MyClass.cpp"
I wrote my declarition in the .h file
class String
{
String (const char * cstr = 0);
};
and I used inline in another .cpp file (implementation)
inline String::String(const char * cstr)
{
//code ...
}
then I use g++ and get this:
Undefined symbols for architecture x86_64:
"String::String(char const*)", referenced from:
_main in test-d389f3.o
ld: symbol(s) not found for architecture x86_64
solution: do not write inline when declarition and implementation is independent.
When I using clang to compile a C++ program, I have the similar error.
But after I changing to use chang++, the compilation worked.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
GCC linker can’t find standard library?
I am trying to mess with this C++ book I got for the holidays, I am coming from a limited understanding of python so this stuff is real strange to me.
I typed out this code from one of the first lessons into my text editor and saved it as a .cpp file.
#include <iostream>
int main()
{
std::cout << "Enter two numbers:" << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The sum of " << v1 << " and " << v2
<< " is " << v1 + v2 << std::endl;
return 0;
}
but my terminal gives this crazy output when i try to compile it, whats going on?
Raymond-Weisss-MacBook-Pro:c++ Raylug$ gcc prog2.cpp
Undefined symbols for architecture x86_64:
"std::basic_istream<char, std::char_traits<char> >::operator>>(int&)", referenced from:
_main in cckdLEun.o
"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> >&))", referenced from:
_main in cckdLEun.o
"std::basic_ostream<char, std::char_traits<char> >::operator<<(int)", referenced from:
_main in cckdLEun.o
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in cckdLEun.o
"std::ios_base::Init::~Init()", referenced from:
___tcf_0 in cckdLEun.o
"std::cin", referenced from:
_main in cckdLEun.o
"std::cout", referenced from:
_main in cckdLEun.o
"std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
_main in cckdLEun.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in cckdLEun.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
Raymond-Weisss-MacBook-Pro:c++ Raylug$
Yes, you should use g++ to compile C++ instead of gcc, but it's probably worth elaborating on the answer since you say you're new to using compilers.
GCC stands for the GNU Compiler Collection and is a collection of programs that can be used to compile source code for various languages. The command gcc provides the external interface for users to compile their programs. The gcc command will attempt to determine the language you want to compile from the file extensions on the source files. For example, a file named hello.c will compile as C, a file named foo.cpp will compile as C++, and a file named bar.m will compile as Objective-C.
You can give the -x option to explicitly specify which language to compile, regardless of file extension. For example, gcc -x c++ main.c will compile main.c as a C++ file, despite having the .c extension.
However, even though gcc will determine that your files are C++, it still won't link to the C++ standard library by default. This library must be linked to to compile anything but the most simple C++ files. You can link to the GCC implementation of the standard library by adding -lstdc++ to your options. So gcc -lstdc++ prog2.cpp should work fine.
However, for convenience, another command is provided for C++ programmers. Namely, g++. The g++ command will automatically link to the C++ standard library, so you don't have to do it explicitly. It also causes .c, .h and .i files to be treated as C++ files.
If you consistently stick with gcc for compiling C and g++, you should have no problems.
You need to use g++ instead of gcc
I'm trying to use Poco C++ library to do the simple http requests in C++ on Mac OS X 10.8.2. I installed Poco, copy-pasted the http_request.cc code from this tutorial, ran it with 'g++ -o http_get http_get.cc -lPocoNet', but got:
Undefined symbols for architecture x86_64:
"Poco::StreamCopier::copyStream(std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&, unsigned long)", referenced from:
_main in ccKuZb1g.o
"Poco::URI::URI(char const*)", referenced from:
_main in ccKuZb1g.o
"Poco::URI::~URI()", referenced from:
_main in ccKuZb1g.o
"Poco::URI::getPathAndQuery() const", referenced from:
_main in ccKuZb1g.o
"Poco::URI::getPort() const", referenced from:
_main in ccKuZb1g.o
"Poco::Exception::displayText() const", referenced from:
_main in ccKuZb1g.o
"typeinfo for Poco::Exception", referenced from:
GCC_except_table1 in ccKuZb1g.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
Have been struggling with this for couple of hours. Any idea how to fix this? Thanks in advance!
the Poco::URI, Poco::StreamCopier classes are in the PocoFoundation library, so you will need to link to that library also.
g++ -o http_get http_get.cc -lPocoNet -lPocoFoundation
You don't appear to have specified the include path for the library and the library to use when compiling your source.
You need to provide the -I and the -L directive to g++ to specify the include path for the library and the library itself respsectively.