So, I'm trying to use the Plugins package to dynamically load a haskell function from a source file. The source file depends on a package foo with module Foo.Bar. I'm running my project in a Cabal sandbox, where I have foo installed. Both my main program, and the module I'm loading with plugins, depend on foo. I always get one of the following two errors:
When I have foo installed in ~/.cabal, I get the error:
GHCi runtime linker: fatal error: I found a duplicate definition for symbol
aizmvszmaizmlibzm0zi1_FooziBar_zdfTypeableBazzuds2_closure
whilst processing object file
/home/joey/.cabal/lib/foo-0.1/ghc-7.6.3/HSfoo-0.1.o
This could be caused by:
* Loading two different object files which export the same symbol
* Specifying the same object file twice on the GHCi command line
* An incorrect `package.conf' entry, causing some object to be
loaded twice.
GHCi cannot safely continue in this situation. Exiting now. Sorry.
When I don't have it installed in ~/.cabal, I get a standard "module not found" error. And when I don't have it installed in my sandbox, I get the same module not found error trying to compile my main program code.
The plugins documentation is scarce at best. Any thoughts on how to solve this?
I got this working by using System.Plugins.Make to actually do the compliation, instead of relying on pre-existing object files. Not a complete solution, doesn't explain the problem, but it works for me for now.
I am trying to complete the installation for some software. According to which I have to add path. I am not getting it how to do that. Please guide me how to do the following steps.
Add the path to Rpa/Tk headers:
-I/usr/include/rpatk
To link to the Rpa/Tk libraries on Linux add the following link options:
-lrpa -lrvm -lrex -lrlib -lm
RVM library uses some math functions from the system math library, that is why you must include '-lm' to include the math library to your project in addition to the Rpa/Tk built libraries:
librpa librex librvm librlib
http://www.rpasearch.com/rpatk/doc/doxygen/rpadoc/html/rpatk_build.html
this will be within your configure script -- you will need to hack this and add the paths to where gcc/cc gets called
give the link to the actual tar.gz
looking at the example code: http://www.rpasearch.com/rpatk/doc/doxygen/rpadoc/html/js-tokenizer_8c-example.html
gcc -I/usr/include/rpatk -o js-tokenizer js-tokenizer.c -lrex -lrlib
so in short :
export LD_LIBRARY_PATH=/usr/include/rpatk:/usr/local/lib:/lib:/usr/lib
then running the configure may fix the issue
where the bit in bold would the path to the includes for this project
I have a CMake module to locate FreeGLUT:
FIND_PATH(FREEGLUT_INCLUDE_DIR NAMES GL/freeglut.h)
FIND_LIBRARY(FREEGLUT_LIBRARY NAMES freeglut freeglut_static)
SET(FREEGLUT_LIBRARIES ${FREEGLUT_LIBRARY})
SET(FREEGLUT_INCLUDE_DIRS ${FREEGLUT_INCLUDE_DIR})
INCLUDE(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(FreeGLUT DEFAULT_MSG FREEGLUT_LIBRARY FREEGLUT_INCLUDE_DIR)
MARK_AS_ADVANCED(FREEGLUT_INCLUDE_DIR FREEGLUT_LIBRARY)
It works fine and locates freeglut_static.lib when I generate NMake Makefiles on Windows. I'm attempting to statically link FreeGLUT into my DLL:
FIND_PACKAGE(FreeGLUT REQUIRED)
ADD_LIBRARY(vti SHARED ${VTI_SOURCES})
ADD_DEFINITIONS("-DBUILD_VTI=1 -DFREEGLUT_STATIC=1")
INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include ${FREEGLUT_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(vti ${FREEGLUT_LIBRARIES})
My source code builds correctly, but when it gets to the linking stage, VC++ fails with:
LINK : fatal error LNK1104: cannot open file 'freeglut.lib'
Which is strange since freeglut.lib isn't mentioned anywhere that I can see in the generated NMake makefiles. It should be trying to link with freeglut_static.lib, which CMake locates and sets in FREEGLUT_LIBRARIES.
What might be causing this?
This is caused with pragma directives in FreeGLUT code (see freeglut_std.h). Using FREEGLUT_STATIC should really fix that for you, but I think you should pass it to CMake without quotes: ADD_DEFINITIONS(-DBUILD_VTI -DFREEGLUT_STATIC)
I'm trying to compile a program which uses the alglib function pearsoncorr2.
Unfortunately I always get compilation errors like the following:
undefined reference to `alglib::real_1d_array::real_1d_array()'
I know that I have to compile all the dependencies of the alglib unit which contains the function I want to use. In my case it's statistics.h.
I'm including all the necessary files (ap.h, statistics.h, alglibinternal.h, alglibmisc.h, linalg.h, specialfunctions.h) when compiling my program, but still I get these undefined reference errors.
I'm using g++ on linux.
What am I doing wrong?
Thanks in advance.
You also need to include the binary part -- i.e., either the *.o files or the *.so library file -- on your final link line. So for example, you probably need to link with linalg.o .
Alglib needs to compile all 13 cpp files before using it.
I have CMakeList.txt to tare care all the dependencies for me.
I am trying to get PhysX working using Ubuntu.
First, I downloaded the SDK here:
http://developer.download.nvidia.com/PhysX/2.8.1/PhysX_2.8.1_SDK_CoreLinux_deb.tar.gz
Next, I extracted the files and installed each package with:
dpkg -i filename.deb
This gives me the following files located in /usr/lib/PhysX/v2.8.1:
libNxCharacter.so
libNxCooking.so
libPhysXCore.so
libNxCharacter.so.1
libNxCooking.so.1
libPhysXCore.so.1
Next, I created symbolic links to /usr/lib:
sudo ln -s /usr/lib/PhysX/v2.8.1/libNxCharacter.so.1 /usr/lib/libNxCharacter.so.1
sudo ln -s /usr/lib/PhysX/v2.8.1/libNxCooking.so.1 /usr/lib/libNxCooking.so.1
sudo ln -s /usr/lib/PhysX/v2.8.1/libPhysXCore.so.1 /usr/lib/libPhysXCore.so.1
Now, using Eclipse, I have specified the following libraries (-l):
libNxCharacter.so.1
libNxCooking.so.1
libPhysXCore.so.1
And the following search paths just in case (-L):
/usr/lib/PhysX/v2.8.1
/usr/lib
Also, as Gerald Kaszuba suggested, I added the following include paths (-I):
/usr/lib/PhysX/v2.8.1
/usr/lib
Then, I attempted to compile the following code:
#include "NxPhysics.h"
NxPhysicsSDK* gPhysicsSDK = NULL;
NxScene* gScene = NULL;
NxVec3 gDefaultGravity(0,-9.8,0);
void InitNx()
{
gPhysicsSDK = NxCreatePhysicsSDK(NX_PHYSICS_SDK_VERSION);
if (!gPhysicsSDK)
{
std::cout<<"Error"<<std::endl;
return;
}
NxSceneDesc sceneDesc;
sceneDesc.gravity = gDefaultGravity;
gScene = gPhysicsSDK->createScene(sceneDesc);
}
int main(int arc, char** argv)
{
InitNx();
return 0;
}
The first error I get is:
NxPhysics.h: No such file or directory
Which tells me that the project is obviously not linking properly. Can anyone tell me what I have done wrong, or what else I need to do to get my project to compile? I am using the GCC C++ Compiler. Thanks in advance!
It looks like you're confusing header files with library files. NxPhysics.h is a source code header file. Header files are needed when compiling source code (not when linking). It's probably located in a place like /usr/include or /usr/include/PhysX/v2.8.1, or similar. Find the real location of this file and make sure you use the -I option to tell the compiler where it is, as Gerald Kaszuba suggests.
The libraries are needed when linking the compiled object files (and not when compiling). You'll need to deal with this later with the -L and -l options.
Note: depending on how you invoke gcc, you can have it do compiling and then linking with a single invocation, but behind the scenes it still does a compile step then a link step.
EDIT: Extra explanation added...
When building a binary using a C/C++ compiler, the compiler reads the source code (.c or .cpp files). While reading it, there are frequently #include statements that are used to read .h files. The #include statements give the names of files that must be loaded. Those exact files must exist in the include path. In your case, a file with the exact name "NxPhysics.h" must be found somewhere in the include path. Typically, /usr/include is in the path by default, and so is the current directory. If the headers are somewhere else such as a subdirectory of /usr/include, then you always need to explicitly tell the compiler where to look using the -I command-line switches (or sometimes with environment variables or other system configuration methods).
A .h header file typically includes data structure declarations, inline function definitions, function and class declarations, and #define macros. When the compilation is done, a .o object file is created. The compiler does not know about .so or .a libraries and cannot use them in any way, other than to embed a little bit of helper information for the linker. Note that the compiler also embeds some "header" information in the object files. I put "header" in quotes because the information only roughly corresponds to what may or may not be found in the .h files. It includes a binary representation of all exported declarations. No macros are found there. I believe that inline functions are omitted as well (though I could be wrong there).
Once all of the .o files exist, it is time for another program to take over: the linker. The linker knows nothing of source code files or .h header files. It only cares about binary libraries and object files. You give it a collection of libraries and object files. In their "headers" they list what things (data types, functions, etc.) they define and what things they need someone else to define. The linker then matches up requests for definitions from one module with actual definitions for other modules. It checks to make sure there aren't multiple conflicting definitions, and if building an executable, it makes sure that all requests for definitions are fulfilled.
There are some notable caveats to the above description. First, it is possible to call gcc once and get it to do both compiling and linking, e.g.
gcc hello.c -o hello
will first compile hello.c to memory or to a temporary file, then it will link against the standard libraries and write out the hello executable. Even though it's only one call to gcc, both steps are still being performed sequentially, as a convenience to you. I'll skip describing some of the details of dynamic libraries for now.
If you're a Java programmer, then some of the above might be a little confusing. I believe that .net works like Java, so the following discussion should apply to C# and the other .net languages. Java is syntactically a much simpler language than C and C++. It lacks macros and it lacks true templates (generics are a very weak form of templates). Because of this, Java skips the need for separate declaration (.h) and definition (.c) files. It is also able to embed all the relevant information in the object file (.class for Java). This makes it so that both the compiler and the linker can use the .class files directly.
The problem was indeed with my include paths. Here is the relevant command:
g++ -I/usr/include/PhysX/v2.8.1/SDKs/PhysXLoader/include -I/usr/include -I/usr/include/PhysX/v2.8.1/LowLevel/API/include -I/usr/include/PhysX/v2.8.1/LowLevel/hlcommon/include -I/usr/include/PhysX/v2.8.1/SDKs/Foundation/include -I/usr/include/PhysX/v2.8.1/SDKs/Cooking/include -I/usr/include/PhysX/v2.8.1/SDKs/NxCharacter/include -I/usr/include/PhysX/v2.8.1/SDKs/Physics/include -O0 -g3 -DNX_DISABLE_FLUIDS -DLINUX -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o"main.o" "../main.cpp"
Also, for the linker, only "PhysXLoader" was needed (same as Windows). Thus, I have:
g++ -o"PhysXSetupTest" ./main.o -lglut -lPhysXLoader
While installing I got the following error
*
dpkg: dependency problems prevent configuration of libphysx-dev-2.8.1:
libphysx-dev-2.8.1 depends on libphysx-2.8.1 (= 2.8.1-4); however:
Package libphysx-2.8.1 is not configured yet.
dpkg: error processing libphysx-dev-2.8.1 (--install):
dependency problems - leaving unconfigured
Errors were encountered while processing:
*
So I reinstalled *libphysx-2.8.1_4_i386.deb*
sudo dpkg -i libphysx-2.8.1_4_i386.deb