Linking error with Poco Net - c++

I am stuck trying to get some code to build using the POCO libraries.
I get the following when I try to build
Undefined symbols for architecture x86_64:
"Poco::Net::SocketAddress::SocketAddress(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned short)", referenced from:
.....
ld: symbol(s) not found for architecture x86_64
Now here is the catch: I am linking with -lPocoFoundation -lPocoNet -lPocoUtil
What am I missing?
(I should say that I am compiling with clang on Mac OS X 10.8.2

I have the same problem. I found change xcode build setting is useful.
Change C++ Standard Library from libc++(LLVM C++ standard library with C++ 11 support) to libstdc++(GNU C++ standard library). Then it will pass building.

I had the same problem and it worked fine for me what Leezi wrote. I'm using version 1.4.6.
The only thing what I had to do more is to compile the Poco library again (because it was compiled for clang with C++11 support):
./configure --config=Darwin64-gcc
make
sudo make install
The other way what you can do is to compile Poco library with C++11 support, but it's a little bit complicated.
First I had to modify two source file in Foundation:
Foundation/src/NumberParser.cpp:
127c127
< return std::sscanf(s.c_str(), "%"I64_FMT"d%c", &value, &temp) == 1;
---
> return std::sscanf(s.c_str(), "%" I64_FMT "d%c", &value, &temp) == 1;
144c144
< return std::sscanf(s.c_str(), "%"I64_FMT"u%c", &value, &temp) == 1;
---
> return std::sscanf(s.c_str(), "%" I64_FMT "u%c", &value, &temp) == 1;
161c161
< return std::sscanf(s.c_str(), "%"I64_FMT"x%c", &value, &temp) == 1;
---
> return std::sscanf(s.c_str(), "%" I64_FMT "x%c", &value, &temp) == 1;
Foundation/src/DirectoryWatcher.cpp:
51a52
> #include <unistd.h>
I modified build/config/Darwin-clang file too:
55,56c55,56
< CXXFLAGS = $(ARCHFLAGS) -Wall -Wno-sign-compare
< LINKFLAGS = $(ARCHFLAGS)
---
> CXXFLAGS = $(ARCHFLAGS) -Wall -Wno-sign-compare -std=c++11 -stdlib=libc++
> LINKFLAGS = $(ARCHFLAGS) -stdlib=libc++
80c80
< SYSLIBS = -ldl
---
> SYSLIBS = -ldl -lstdc++
I needed only for static libraries, so I only compiled that:
./configure --static --omit=Data --config=Darwin64-clang --poquito -no-tests -no-samples -no-shared
make clean
make
sudo make install
If you need for samples and tests too, then I think you should make an xcode project and set up it or go deep inside the makefiles...
I hope this help...

Related

Undefined reference to printf when using GCC LD cross compiler

I have an issue on gcc 9.3.1 version for ARM, my code have two file that object_1.c is empty file and for main.c as
unsigned char test = 100;
int main(void)
{
/*Write code here*/
test++;
printf("Test lib");
return 0;
}
my command when linking as the example:
<gcc_path>/bin/arm-none-eabi-ld.exe -L<gcc_path>/arm-none-eabi/lib -L<gcc_path>/lib/gcc/arm-none-eabi/9.3.1 -lc -lm -T linker.ld object_1.o main.o -o run.elf
I have tried some ideas but it is not work. Could anyone help me with some ideas?

main function not being detected when compiled

I am trying to run a program that opens a window. the purpose is to get the program started opening a window is the start of all programs right?
But when I run my code for some reason I get this error:
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)
However, in my code I do have the main() function so why am I getting this error?
This is my code:
#include <SDL2/SDL.h>
#include <SDL2_image/SDL_image.h>
#include <SDL2_ttf/SDL_ttf.h>
#include <stdio.h>
int main(){
if(SDL_Init( SDL_INIT_EVERYTHING ) < 0){
std::cout << "error 1\n";
std::cout << SDL_GetError();
std::cout << "\n";
return -1;
}
if(TTF_Init() < 0){
std::cout << "error 2\n";
std::cout << TTF_GetError();
std::cout << "\n";
return -1;
}
SDL_Window* window = SDL_CreateWindow("test", 0, 0, 500, 500, 0);
if(!window){
std::cout << "error 3\n";
std::cout << SDL_GetError();
std::cout << "\n";
return -1;
}
int windowid = SDL_GetWindowID(window);
SDL_Renderer* Renderer = SDL_CreateRenderer(window, -1, 0);
running = true;
SDL_Event event;
while(running){
while(SDL_PollEvent(&event)){
if(event.type == SDL_WindowEvent){
if(event.window.windowID == windowid){
if(event.window.type == SDL_WindowClose){
Destroywindow(window);
running = false;
}
}
}
}
}
return 0;
}
my make file looks like this:
#!/bin/bash
brew update
brew install sdl2
g++ -o /Users/mikahshattuck/noneproject/none2019-05-0909-22-
14:2:/none.app/Contents/MacOS/mainrun.cpp -I /Library/Frameworks -l
SDL2
exit 0
this is the full out:
Already up-to-date.
Warning: sdl2 2.0.9_1 is already installed and up-to-date
To reinstall 2.0.9_1, run `brew reinstall sdl2`
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)
logout
Saving session...
...copying shared history...
...saving history...truncating history files...
...completed.
[Process completed]
thank you in advance
When using SDL on macOS or Windows, you need to add -Dmain=SDL_main to your compile flags and -lSDL2main to your link flags. Since you're using Homebrew, you can make it easier and just use pkg-config to get the correct flags. Use this compiler command as a template and adapt it to your needs:
g++ $(pkg-config --cflags sdl2) -I /Library/Frameworks source.cpp -o output_executable $(pkg-config --libs sdl2)
However, it seems you are also using SDL_ttf, not just plain SDL. In this case, you should probably use SDL2_ttf instead of sdl2 as the package argument of pkg-config:
g++ $(pkg-config --cflags SDL2_ttf) -I /Library/Frameworks source.cpp -o output_executable $(pkg-config --libs SDL2_ttf)
The SDL2_ttf package depends on the sdl2 package, so using SDL2_ttf will also emit the needed flags for sdl2.
The names of the pkg-config packages correspond to *.pc files installed by Homebrew into /usr/local/lib/pkgconfig.

Xcode gives Mach-O linker error: "_JNI_CreateJavaVM", referenced from: _main in main.o

I get this error from testing JNI:
Undefined symbols for architecture x86_64:
"_JNI_CreateJavaVM", referenced from:
_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)
Here is c++ code:
#include <jni.h>
#include <iostream>
using namespace std;
int main()
{
int res;
JavaVMInitArgs vm_args;
JavaVMOption options[3];
JavaVM *jvm;
JNIEnv *env;
jmethodID mid;
options[0].optionString = "-Djava.compiler=NONE";
options[1].optionString = "-Djava.class.path = /Users/stephen/course/test/Test";
options[2].optionString = "-verbose:NONE";
vm_args.version = JNI_VERSION_1_8;
vm_args.nOptions = 3;
vm_args.options = options;
vm_args.ignoreUnrecognized = JNI_TRUE;
res = JNI_CreateJavaVM(&jvm,(void**)&env,&vm_args);
if(res == JNI_ERR){
cout << "Error invoking the JVM";
return 1;
}
cout <<"create JVM successfully!"<<endl;
jclass cls = env->FindClass("/Users/stephen/course/Qt-project/test/Test");
if(cls != 0){
cout<<"find class successfully!" << endl;
}
mid = env->GetMethodID(cls,"sayHello","stephen");
if(mid != 0){
cout<<"Invoke method successfully!" << endl;
}
jvm->DestroyJavaVM();
return 0;
}
Here is java code:
public class Test
{
public static void sayHello(String s){
System.out.print("hello I am" + s + "\n");
}
}
I add the include path of " jdk/include; jdk/include/darwin" the project, also I add lib path of " jdk/jre/lib/server" to the project to get the libjvm.dylib. The c++ standard library of my project is libstdc++(gnu c++ standard library.
But I can't solve this problem as expected.
Take a look here for a sample code where JVM library is linked with your project:
https://github.com/mkowsiak/jnicookbook/tree/master/recipes/recipeNo028
Take a look at Makefile. Especially, here:
main: recipeNo028_main.o
ld -o lib/recipeNo028_main -L${JAVA_HOME}/jre/lib/server/ \
-ljvm \
$(MAC_OS_FLAGS) \
lib/recipeNo028_main.o
where jvm lib is linked with the code, and here:
CC=llvm-gcc
MAC_OS_FLAGS=-rpath ${JAVA_HOME}/jre/lib/server -L/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -demangle -dynamic -arch x86_64 -macosx_version_min 10.12.0 -lSystem
where all required libs are added to your code as well. It should work. Try to compile sample code. You can find more samples here: http://jnicookbook.owsiak.org
Update
How to use arbitrary JDK version for compilation.
First, take a look at all installations you have
/usr/libexec/java_home -V
This will produce something like this
/usr/libexec/java_home -V
Matching Java Virtual Machines (4):
9, x86_64: "Java SE 9" /Library/Java/JavaVirtualMachines/jdk-9.jdk/Contents/Home
1.8.0_144, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home
1.8.0_111, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home
1.7.0_80, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home
Then, before running make, simply set JAVA_HOME to whatever you like
export JAVA_HOME=$(/usr/libexec/java_home -v 9)
Now, your code will use version that you have chosen.

Octave from QT: undefined reference

I would like to run Octave script from Qt GUI application.
Here is .pro file:
...
win32 {
INCLUDEPATH += c:/Octave/Octave-4.2.1/include/octave-4.2.1/octave
LIBS += c:/Octave/Octave-4.2.1/lib/octave/4.2.1/liboctave.dll.a \
c:/Octave/Octave-4.2.1/lib/octave/4.2.1/liboctinterp.dll.a
DEPENDPATH += c:/Octave/Octave-4.2.1/bin
}
...
Here is .cpp file (example is taken from docs):
#include <iostream>
#include <octave/oct.h>
#include <octave/octave.h>
#include <octave/parse.h>
#include <octave/interpreter.h>
int
main (void)
{
string_vector argv (2);
argv(0) = "embedded";
argv(1) = "-q";
octave_main (2, argv.c_str_vec (), 1);
octave_idx_type n = 2;
octave_value_list in;
for (octave_idx_type i = 0; i < n; i++)
in(i) = octave_value (5 * (i + 2));
octave_value_list out = feval ("gcd", in, 1);
if (out.length () > 0)
std::cout << "GCD of ["
<< in(0).int_value ()
<< ", "
<< in(1).int_value ()
<< "] is " << out(0).int_value ()
<< std::endl;
else
std::cout << "invalid\n";
clean_up_and_exit (0);
}
When I am trying to compile C++ code from Qt Creator I have the following error:
undefined reference to feval(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, octave_value_list const&, int)
I also have the following errors from compiler:
undefined reference to Array<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::nil_rep()
undefined reference to Array<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::resize_fill_value() const
undefined reference to Array<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::resize_fill_value() const
but when I Ctrl+Click on Array or feval - Qt Creator opens the appropriate files.
I can also compile the example c++ file using the following command from Octave GUI:
mkoctfile --link-stand-alone embedded.cc -o embedded
What library/path should I add?
Thank you very much in advance.
If you run mkoctfile on your example from above (I copied it into main.cc) with verbose, you'll see all flags needed:
mkoctfile -v --link-stand-alone main.cc
g++ -std=gnu++11 -c -fPIC -I/usr/local/include/octave-4.2.0/octave/.. -I/usr/local/include/octave-4.2.0/octave -I/usr/local/include -pthread -fopenmp -g -O2 main.cc -o main.o
g++ -std=gnu++11 -I/usr/local/include/octave-4.2.0/octave/.. -I/usr/local/include/octave-4.2.0/octave -I/usr/local/include -pthread -fopenmp -g -O2 -rdynamic -fPIC main.o -L/usr/local/lib/octave/4.2.0 -L/usr/local/lib -loctinterp -loctave
Now you have to add these to your QtCreator. (I guess -std=gnu++11 is missing)
It seems from the error that gcd function does not exist, or it cannot find reference to it. I don't know about gcd function whether it is part of octave or it is your custom defined, but surely it's missing a reference to it.

When using dyn.load in R I do not get any error messages, but my .dll file does not load

I am following an example from the 'Writing R extensions manual' version 3.3.1. Specifically, I am working with c++ code, which I have saved in file out.cpp, that is on page 115 of that manual shown below:
#include <R.h>
#include <Rinternals.h>
SEXP out(SEXP x, SEXP y)
{
int nx = length(x), ny = length(y);
SEXP ans = PROTECT(allocMatrix(REALSXP, nx, ny));
double *rx = REAL(x), *ry = REAL(y), *rans = REAL(ans);
for(int i = 0; i < nx; i++) {
double tmp = rx[i];
for(int j = 0; j < ny; j++)
rans[i + nx*j] = tmp * ry[j];
}
UNPROTECT(1);
return ans;
}
I have a windows computer and use cygwin command line. There I typed R CMD SHLIB out.cpp and get the following result:
cygwin warning:
MS-DOS style path detected: C:/R-3.2.3/etc/x64/Makeconf
Preferred POSIX equivalent is: /cygdrive/c/R-3.2.3/etc/x64/Makeconf
CYGWIN environment variable option "nodosfilewarning" turns off this warning.
Consult the user's guide for more details about POSIX paths:
http://cygwin.com/cygwin-ug-net/using.html#using-pathnames
g++ -m64 -I"C:/R-3.2.3/include" -DNDEBUG -I"d:/RCompile/r- compiling/local/local323/include" -O2 -Wall -mtune=core2 -c out.cpp -o out.o
g++ -m64 -shared -s -static-libgcc -o out.dll tmp.def out.o -Ld:/RCompile/r-compiling/local/local323/lib/x64 -Ld:/RCompile/r-compiling/local/local323/lib -LC:/R-3.2.3/bin/x64 -lR
I think there is nothing wrong with this, right? Then when I go into Rstudio I type
dyn.load(paste("C:/Rextensions/out",
.Platform$dynlib.ext, sep = ""),local=FALSE)
which gives me no error message whatsoever. But when I run
is.loaded('out')
I get 'FALSE', so I am never able to upload out.dll. Could you help me with this please?
P.S.: I know how to run functions like this one using Rcpp, so please don't tell me to do that instead. What I am trying to do is understand really well the Writing Extensions manual so I hope I can go through all of their examples in that document.
Thank you.