I looked at this post, but it did not help. Builder returns me this:
/cygdrive/c/Users/Itun/workspace/VoxEngine/Debug/../src/main.cpp:30: undefined reference to _glEnable
/cygdrive/c/Users/Itun/workspace/VoxEngine/Debug/../src/main.cpp:31: undefined reference to _glClearColor'`.
What do -lglut32 -lglu32 -lopengl32 flags mean? Where are the libs?
How to create OpenGL project under Cygwin with Eclipse?
UPDATE:
I add -I/usr/include/opengl to g++ and it starts to work. In this folder there is a single file GL.dll. How does this dll influence to the compilation?
The flag -l -lglut32 -lglu32 -lopengl32 tell the linker to link against libraries libglut32, libglu32 and libopengl32
However your error indicated you didn't include any OpenGL header files. (#include <GL/gl.h>, #include <GL/glu.h>)
Cygwin keeps to the Unix way and places libraries in $CYGWINPREFIX/usr/lib and includes in $CYGWINPREFIX/usr/include.
Related
I can already cross-compile some simple applications using x86_64-w64-mingw32-g++. However, I cannot find out how to find libraries for my project (in my case I need to use SDL2 and SDL2_image). I know how to install these libraries already (sudo apt install libsdl2-dev libsdl2-image-dev), but apt search does not show any libraries for x86_64-w640mingw32-g++.
Here are the links I've looked at:
https://arrayfire.com/cross-compile-to-windows-from-linux/
https://stackoverflow.com/questions/2033997/how-to-compile-for-windows-on-linux-with-gcc-g
Is there a way to use precompiled libraries, or do I need to add the source code in my project?
Update: I followed the instructions advised by Laurent Jospin, and can compile a "Hello World" program that works with Windows (I sent it to a friend to test). However, I cannot compile my program that uses SDL.
Terminal output:
$ /opt/mxe/usr/bin/x86_64-w64-mingw32.shared-g++ -O3 main.o Game.o TextureManager2D.o Map.o Entity.o Player.o -mwindows -lSDL2 -lSDL2_image -o ../../../endeavour-client.exe
/opt/mxe/usr/lib/gcc/x86_64-w64-mingw32.shared/5.5.0/../../../../x86_64-w64-mingw32.shared/lib/../lib/libmingw32.a(lib64_libmingw32_a-crt0_c.o): In function `main':
/opt/mxe/tmp-gcc-x86_64-w64-mingw32.shared/gcc-5.5.0.build_.crt/../gcc-5.5.0.build_/mingw-w64-v8.0.0/mingw-w64-crt/crt/crt0_c.c:18: undefined reference to `WinMain'
collect2: error: ld returned 1 exit status
$
Changing -mwindows to -municode, -d UNICODE, -Wl,-subsystem,windows, or removing it all do not work.
What you are looking for is the M Cross Environnement: https://mxe.cc/
It is a set of makefiles able to download and cross compile a selection of popular libraries for windows on linux. By default it builds static libraries, such that you ends up with .a libraries that get merged into the final .exe, meaning you don't have to worry about shipping the dlls with your app. But if you prefer a modular structure, it can also builds some dlls.
The list of libraries they do provide is quite impressive. If a library is missing on the other hand you can still install it by copying the corresponding header files and dlls. In some specific situation you might have to cross-compile one of your dependency (I had to do that for an app using ruby scripting. The official windows build of ruby is somehow incompatible with certain libraries built with mingw. But this is rather exceptional).
The correct command is:
$ /opt/mxe/usr/bin/x86_64-w64-mingw32.shared-g++ -O3 main.o Game.o TextureManager2D.o Map.o Entity.o Player.o -mwindows -lmingw32 -lSDl2main -lSDL2 -lSDL2_image -o ../../../endeavour-client.exe
Edit: Note that having -lmingw32 -lSDL2main -lSDL2 -lSDL2_image in that exact order is vital.
I, being the absolute idiot that I am, forgot to include the -lmingw32 AND -lSDL2main flags in the command, which is why there is the issue with WinMain not being found. When using MinGW-w64 as the cross compiler, the -lmingw32 library has to be included. And of course, SDL requires the -lSDl2main flag when building for windows (but interestingly enough, not on Linux). Here are the links I used. (I had an uncommon insight in replacing -lSDLmain with -lSDL2main, as the links are pretty old.)
MinGW Starter Guide
Code::Blocks Forums
SO: Undefined Reference to WinMain
I am using Windows 7, Code::Blocks and MinGW. I have little to no experience when it comes to compiling/building anything, especially when Code::Blocks doesn't use makefiles.
I downloaded SDL2-devel-2.0.0-mingw.tar.gz (SDL Development Libraries) from http://www.libsdl.org/tmp/download-2.0.php, and I'd like to create a standalone executable using SDL2 libraries, but so far I've always had to bundle the SDL2.dll file with the executable to make it work.
I've heard that I can not static-link dynamic libraries, so my only option seems to be doing something with the source files using the file SDL2-2.0.0.tar.gz (Source Code) from the link I mentioned above. However, I do not know what I should do with those.
What I managed to try with the source files is importing the Visual Studio project to Code::Blocks and building it, but it tells me "sdl-config No such file or directory" (I do not know what triggered that). I'm also not sure if building merely gives me an executable, with which I do not know what I can do to link it to my own executable.
A fool proof idiot's step by step guide would be the best bet to solve this case.
EDIT:
I managed to compile the SDL libraries with the guide Jonas provided, and got a libSDL2.a file.
At first I only added the path of libSDL2.a to "Link libraries:" -section of Code::Blocks, but I got a bunch of errors such as "SDL_Init() not declared in this scope".
In addition to the libSDL2.a path, I also added the path of SDL2-2.0.0\include to the Compiler's search directory as well as the path of SDL2-2.0.0\build.libs to the Linker's search directory. I also wrote this to my test file: #include "SDL.h". My test file now looks like this:
#include "SDL.h"
int main( int argc, char* args[] ) {
//Start SDL
SDL_Init( SDL_INIT_EVERYTHING );
//Quit SDL
SDL_Quit();
return 0;
}
It appears it did fix the declaration problem, but now Code::Blocks opened a SDL_mmjoystick.c file and gave me even more errors: "undefined reference to 'waveInClose#4'", "undefined reference to 'waveOutClose#4'", "undefined reference to 'joyGetNumDevs#0'" and tons of other ones.
Here's a screenshot of what's happening, note the different color of #include texts, I'm not sure why that happens: http://gyazo.com/00656a9c1e57a2bd0db1414fa7d68ced.png
I am not sure how to correctly take this library into use. Any help in this case, or should I make another question for it?
EDIT:
I added -lSDL2 to the linker options and deleted the other parameters. Now it builds fine:
mingw32-g++.exe -Wall -fexceptions -g -IC:\Users\User\Desktop\SDL2-2.0.0\include -c "C:\Users\User\Desktop\CppProjects\SDL project\main.cpp" -o obj\Debug\main.o
mingw32-g++.exe -Wall -fexceptions -g -IC:\Users\User\Desktop\SDL2-2.0.0\include -c "C:\Users\User\Desktop\CppProjects\SDL project\thetestfile.cpp" -o obj\Debug\thetestfile.o
mingw32-g++.exe -LC:\Users\User\Desktop\SDL2-2.0.0\build\.libs -o "bin\Debug\SDL project.exe" obj\Debug\main.o obj\Debug\thetestfile.o -lSDL2 ..\..\SDL2-2.0.0\build\.libs\libSDL2.a C:\Users\User\Desktop\SDL2-2.0.0\build\.libs\libSDL2.a -mwindows
Output size is 945.80 KB
Process terminated with status 0 (0 minutes, 1 seconds)
0 errors, 0 warnings (0 minutes, 1 seconds)
But when I try to run it, it says my computer lacks SDL2.dll, while the whole point was to static-link.
So currently I have the path to build/.libs in my Link libraries -settings, -lSDL2 in the Other linker options, and for search directories I have the path to SDL2-2.0.0/include for the compiler and SDL2-2.0.0/build/.libs for the linker.
In the build/.libs directory I can also see libSDL2.a, libSDL2.dll.a, libSDL2.la and libSDL2.lai files, which I don't know what they are.
It's not necessary to recompile the library,
SDL2 is given with static-link library named "libSDL2.a"
on the folder "SDL2-2.0.0\i686-w64-mingw32\lib\".
Just be sure to add these options to the linker :
"-lmingw32 -lSDL2main -lSDL2 -mwindows -lm -ldinput8 -ldxguid -ldxerr8 -luser32 -lgdi32 -lwinmm -limm32 -lole32 -loleaut32 -lshell32 -lversion -luuid -static-libgcc"
on Code:Blocks at "Project / Build Options... / Linket settings / Other linker options"
These options allow you to link with what SDL2.dll was using.
You can retreive them on the file "SDL2-2.0.0\i686-w64-mingw32\bin\sdl2-config"
The magical trick is to delete or rename the file "libSDL2.dll.a"
on the folder "SDL2-2.0.0\i686-w64-mingw32\lib\".
I added a "-" before to keep it in case I need it.
I don't know why this librairy overcomes the other and a clue would be appreciated.
I tried with Code::Blocks 12.11 MinGW32 and it worked.
If you run with some projects that use dynamic-link
and some other which use static-link, you will have to
keep your librairies in two different folders knowing that
"libSDL2main.a" will be in those two.
Sorry for my writing, I'm not used to write in english.
Mike
I need to use libcurl in a piece of software I am writing on my ubuntu machine. I am using Eclipse to write and compile all of the software. When I put the libcurl files in the same folder as the .cpp file, and include the curl.h file in the header, When I attempt to compile the program, It comes up with these errors:
Building target: sms
Invoking: GCC C++ Linker
g++ -o"sms" ./src/sms.o
./src/sms.o: In function `main':
/home/geekman/workspace/sms/Debug/../src/sms.cpp:38: undefined reference to `curl_easy_init'
/home/geekman/workspace/sms/Debug/../src/sms.cpp:42: undefined reference to `curl_easy_setopt'
/home/geekman/workspace/sms/Debug/../src/sms.cpp:44: undefined reference to `curl_easy_setopt'
/home/geekman/workspace/sms/Debug/../src/sms.cpp:46: undefined reference to `curl_easy_perform'
/home/geekman/workspace/sms/Debug/../src/sms.cpp:47: undefined reference to `curl_easy_cleanup'
collect2: ld returned 1 exit status
make: *** [sms] Error 1
I took the contents of the include folder from libcurl, and placed them in the same folder as the .cpp file. then in the header of the .cpp file, I typed:
#include <curl/curl.h>
I also tried:
#include "curl/curl.h"
Any ideas on the problem? Thanks.
Your header file inclusions are just fine; your problem is occurring at the linking step. In order to link against libcurl, you need to add the -lcurl command line option, assuming it's installed in a standard directory:
g++ -o sms ./src/sms.o -lcurl
If it's not installed in a standard directory, you also need to add the -L/path/to/libcurl, e.g. something like:
# Assuming that /home/geekman/workspace/libcurl is where libcurl.a is located
g++ -o sms ./src/sms.o -L/home/geekman/workspace/libcurl -lcurl
Also note that the -lcurl option has to appear after the list of object files you're linking, otherwise it won't link properly.
You can try to use curl-config --libs.
An alternate answer (the first one is excellent). Consider using the output returned by "pkg-config --libs libcurl" as an argument to your compiler.
For example,
CPPFLAGS=`pkg-config --libs libcurl`
g++ $CPPFLAGS myfile.o
Pkg-config is a standard way for open source libraries to communicate to you how to link against them / #include their files.
Anyone who is using ecplise CDT then you need to do following. First on terminal enter
curl-config --libs
On my machine, the result is
-L/usr/lib/i386-linux-gnu -lcurl
then do according to this screenshot and you will be able to compile. btw don't forget to add header files in your code
So you enter library folder path without -L and library name without -l because they will be automatically added by linker.
You have to link the library to your program. With gcc (and most other compilers) you can specify the libraries to link with -lname_wo_lib, e.g. -lcurl
Also see GNU GCC Manual - Options for Linking for a detailed explanation of the options Adam Rosenfield said. For standard search directories, see An Introduction to GCC - for the GNU Compilers gcc and g++ - Setting Search Paths.
In addition to the first answer, I had to link the curlpp library too. So to compile the main.cpp file which included the curlpp I had to do:
g++ main.cpp -lcurl -lcurlpp
Using only one of the two links would return different errors regarding different links. It is important to remind that this only worked because I had installed all the necessary libraries in the standard include folders
I am writing a C++ program in Linux with NetBeans. I am having difficulty setting it up to use external sources/shared objects. I have the .so files from the compiled external package and the source files that go with it.
So far I have:
specified for the project to include all the source and header file directories (under Project properties->Build->C++ Compiler)
specified the .so files that correspond to the external source code (under Project properties->Build-Linker)
When I try to declare an object defined in the external sources NetBeans does not give me any syntax errors and even auto-completes the object name for me. However, when I build the program I get an error saying "undefined reference to" that object.
Am I doing something horribly wrong?
EDIT:
In response to quamrana's question, this is one of the output lines in the console when it attempts to build.
g++ -o dist/Debug/GNU-Linux-x86/JAUSTester build/Debug/GNU-Linux-x86/MainScreen.o build/Debug/GNU-Linux-x86/main.o build/Debug/GNU-Linux-x86/moc_MainScreen.o -L/usr/lib -Wl,-rpath /usr/local/lib/active /usr/local/lib/active/libcxutils.so -Wl,-rpath /usr/local/lib/active/libjauscore.so -Wl,-rpath /usr/local/lib/active/libjausextras.so -Wl,-rpath /usr/local/lib/active/libjausmobility.so -Wl,-rpath /usr/local/lib/active/libtinyxml.so -lQtGui -lQtCore -lpthread
The .so files I want to include are the ones specified there in /usr/local/lib/active/.
I have this assignment due that requires the usage of FLTK. The code is given to us and it should compile straight off of the bat, but I am having linking errors and do not know which other libraries I need to include.
I currently have "opengl32", "fltk_gl", "glu32", and "fltk" included (-l), each of which seem to reduce the number of errors. I compiled FLTK using make with no specified options. Including all of the produced library files doesn't fix the problem, and I'm convinced that it's just some Windows specific problem.
Compile log:
**** Build of configuration Debug for project CG5 ****
make all
Building target: CG5.exe
Invoking: Cygwin C++ Linker
g++ -o"CG5.exe" ./src/draw_routines.o ./src/gl_window.o ./src/my_shapes.o ./src/shape.o ./src/shapes_ui.o ./src/tesselation.o -lopengl32 -lfltk_z -lfltk_gl -lglu32 -lfltk
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x197): undefined reference to `_SelectPalette#12'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x1a7): undefined reference to `_RealizePalette#4'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x1fe): undefined reference to `_glDrawBuffer#4'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x20d): undefined reference to `_glReadBuffer#4'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x23a): undefined reference to `_glGetIntegerv#8'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x2c3): undefined reference to `_glOrtho#48'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../libfltk_gl.a(Fl_Gl_Window.o):Fl_Gl_Window.cxx:(.text+0x2f3): undefined reference to `_SwapBuffers#4'
...and lots more
Thanks a ton for the help.
EDIT: These first few lines are obviously OpenGL related, although I'm still not sure what additional libraries need to be included.
Just a guess: your makefile was written for Linux, and on Cygwin some libraries are either missing or in a different place. You're going to have to examine the makefile, locate the missing libraries, and either move the libs to where the makefile expects them or change the makefile to look in the right place.
The libraries it needs are listed on the line starting g++ (prepend 'lib' to the names after the -l flags)
Sorry for the lack of closure, but I just booted into my Linux netbook and got it working.
-lfltk -lfltk_gl -lGLU -lGL -lXext -lX11 -lm