I'm trying to build a .c file on OSX but I keep getting:
Undefined symbols for architecture x86_64
#include "Test.h"
JNIEXPORT jint JNICALL Java_Test_test
(JNIEnv * env, jclass cls, jbyteArray s, jlong ss, jbyteArray sss, jlong ssss, jbyteArray sssss, jlong ssssss) {
/*printf("Hello World!\n");*/
return 1;
}
Built with:
clang++ -o test -I/Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/include/darwin Test.cpp
Undefined symbols for architecture x86_64: "_main", referenced from:
implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
Is there something I need to install?
clang++ -o test Test.cpp is trying to compile and link to produce a runnable executable. You didn't define main(), so of course this fails when it tries to link the CRT code (which calls the user-supplied main().)
Perhaps you meant to use clang++ -fPIC -shared -o libtest.so Test.cpp -I... (keeping all the other options the same), to make a shared library like JNI needs. Or .dylib or .jnilib, whatever libraries are normally called on your platform.
If you're following a tutorial that didn't tell you how to compile your code, it's probably not a very good tutorial and you should find better documentation.
Related
Given a very simple fortran (95) function and a very simple c++ call to the program, I should be able to compile the program using:
g++ -c main1.cpp
gfortran -c test.f95
g++ main1.o test.o -o run
However, here I get the following error:
ld: warning: object file (test.o) was built for newer macOS version (11.5) than being linked (11.0)
Undefined symbols for architecture arm64:
"hello_()", referenced from:
_main in main1.o
"__gfortran_st_write", referenced from:
_hello_ in test.o
"__gfortran_st_write_done", referenced from:
_hello_ in test.o
"__gfortran_transfer_character_write", referenced from:
hello in test.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Here, adding a -v tag before the -o tag and after the -o tag and the exe run did not solve the problem, as suggested by the error message.
I would like to create my own project using FFMPEG to build a player, but creating a new file to include ffmpeg library seems not easy. I have configure the ffmpeg and make build.
./configure
./make
The ffmpeg hello world program (myffmpeg.c):
#include <libavformat/avformat.h>
int main(int argc, char *argv[]) {
av_register_all();
return 0;
}
but it shows
clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated
Undefined symbols for architecture x86_64:
"av_register_all()", referenced from:
_main in myffmpeg-61ec1b.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation
When I try to link the allformats.o file, which has av_register_all function inside. I got:
clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated
Undefined symbols for architecture x86_64:
"_av_register_input_format", referenced from:
_register_all in allformats.o
"_av_register_output_format", referenced from:
_register_all in allformats.o
"_avcodec_register_all", referenced from:
_register_all in allformats.o
"_ff_a64_muxer", referenced from:
_register_all in allformats.o
...
"_ff_yuv4mpegpipe_muxer", referenced from:
_register_all in allformats.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
It should be my bad Makefile knowledge, could anyone give me some hint on how to call ffmpeg library functions? Or even how to modify the Makefile to build my own program? Thanks!
*Update:
It could be my compiling command problem, is it the way to compile?
g++ myffmpeg.c
maybe the problem is that c++ is decorating functions. So the same function compiled with C compiler and C++ looks different to linker. try this:
extern "C"
{
#include <libavformat/avformat.h>
}
this code means that you told your compiler to not decorate functions in that file.
I think I could answer myself.
g++ -o main.o main.c `pkg-config --cflags --libs libavformat`
I don't know the reason now, it is from https://soledadpenades.com/2009/11/24/linking-with-ffmpegs-libav/
We still need the extern, see answer below.
Snippet from Recompiling libiconv, gettext undefined symbols occurring after an already successful install ; thought to make it its own question.
Trying to use libiconv in a simple .c file:
#include <iconv.h>
// works: gcc -m32 -I/usr/local/include -liconv -o test-iconv.exe test-iconv.c
// does NOT work: gcc -I/usr/local/include -liconv -o test-iconv.exe test-iconv.c
int main(int argc, char **argv) {
iconv_t conv = iconv_open("ISO8859-1", "UTF-8");
if (conv != (iconv_t) -1) {
return 0;
}
return 1;
}
If I do not specify -m32 for gcc then I received the following error:
$ gcc -I/usr/local/include -liconv -o test-iconv.exe test-iconv.c
Undefined symbols for architecture x86_64:
"_libiconv_open", referenced from:
_main in ccr9tTic.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
When you 'install' a library, the library has already been built and the installation cannot change whether it is a 32-bit or 64-bit library.
What controls whether a library is for 32-bit or 64-bit (or both, if you're on macOS Sierra or Mac OS X) is the way the object files are compiled. If you compile with gcc -m32, the object files will be 32-bit and the library will be 32-bit; if you compile with -m64, they'll be 64-bit. If you compile with neither option, you'll get a default behaviour, and the default depends on the platform and how the compiler was built. If you're using one of the Mac operating systems, it is possible to compile both the 32-bit and 64-bit versions into a single object file, and then create a library that contains both 32-bit and 64-bit.
By the looks of it, you need to ensure that you compile libiconv with the 64-bit options. You might need to use ./configure CC='gcc -m64' CXX=g++ -m64… or something similar to force 64-bit compilations — it is a trick I sometimes use.
I try to use boost filesystem on my Mac. I only added the following header and got an error when I tried to compile
# include <boost/filesystem.hpp>
the error is
Undefined symbols for architecture x86_64:
"boost::system::generic_category()", referenced from:
__static_initialization_and_destruction_0(int, int) in cclyDZox.o
"boost::system::system_category()", referenced from:
__static_initialization_and_destruction_0(int, int) in cclyDZox.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
any help is appreciated
You need to add the boost_system library:
-lboost_system
to your build command. Note that you will also need to provide the -lboost_system library too.
If your project thereafter builds but moans with something like
dyld: Library not loaded: libboost_filesystem.dylib
you just need to set the environment variable
DYLD_LIBRARY_PATH
to include your
$BOOST_HOME/lib
directory as mentioned here.
I think you should do
g++ -I~/Documents/boost_1_53_0/include -L~/Documents/boost_1_53_0/stage/lib -std=c++11 test1ver1.cpp -lboost_filesystem -lboost_system
The
-I flag points to where the Boost headers are
-L flag points to where the Boost libs are
-lboost_filesystem and -lboost_system flags enabled the link of your binary and the Boost Filesystem and System shared libraries. (Those should be always after the object or source files)
For instance:
#include <boost/filesystem.hpp>
int main() {
boost::filesystem::path path_household_csv("./test");
}
I have installed GCC 4.7.2 and GMP 5.1.0 and I've written this simple code in main.cpp locate at ~/Desktop:
#include <iostream>
#include <gmp.h>
using namespace std;
int main ()
{
mpz_t a;
mpz_init(a);
mpz_set_ui(a, 42);
cout << "Hello, world!" << endl;
}
I compile it with:
$ g++ main.cpp -o exe
but I get this error message:
Undefined symbols for architecture x86_64:
"___gmpz_init", referenced from:
_main in ccC0FXun.o
"___gmpz_set_ui", referenced from:
_main in ccC0FXun.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
I think it's because it doesn't find the GMP library, am I right?
So how can I link an external library such as GMP in GCC?
Your program works fine for me here using:
g++ main.cpp -o exe -lgmp
Check the GCC documentation for a description of the -l flag.