Using Cygwin to generate and link DLL to another project - c++

C++ newbie here, I have this game engine I am making and I would like to export it into .dll and use it in a sandbox project. It depends on GLFW, spdlog and Vulkan. I am using g++ on Windows with Cygwin.
Here is a simple version of my project:
Sandbox
|----Sandbox.cpp
Engine
|----Engine.h
|----vendor
|----glfw
|----spdlog
So Sandbox.cpp includes <Engine.h>, Engine.h includes <GLFW/glfw3.h>
Here are my commands:
First compile from Engine:
g++ -std=gnu++11 -I someIncludeDir -c someCPP.cpp -o objectFiles.o
Then build dll:
g++ -shared -o objectfiles.o -L./path/to/GLFW/DLL -L"C:\Windows\System32" -lglfw3 -lopengl32 -lgdi32 -lvulkan-1 cygxxx.dll -Wl,--out-implib,libxxx.dll.a
This will give me a cygxxx.dll and libxxx.dll.a.
I moved these 2 files into Sandbox project.
Compile the Sandbox project:
g++ -std=gnu++11 -I../Engine/Engine.h someCPP.cpp -c objectfiles.o
And this is where I got the error saying <GLFW/glfw3.h> not found.
My confusion is, I don't want to include GLFW or Vulkan in my Sandbox project, nor do I want to include them in my compiler flag. Is this even possible?
Please help a C++ noob.

Related

How to compile to SDL2 application to Windows from Linux?

So recently I downloaded the Linux Subsystem on Windows 10, with Ubuntu.
I can compile an SDL2 app to Linux with the g++ command but whenever I try doing it with i686-w64-mingw32-g++ this command, I get an error saying main.cpp:5:9: fatal error: SDL2/SDL.h: No such file or directory.
The command I'm using is i686-w64-mingw32-g++ main.cpp -w -lSDL2 -o main.exe.
https://imgur.com/a/uqcGCoJ
Anyone knows how to fix this? :(
[EDIT]
So now I've tried specifying the directory of the necesary files with this command: g++ main.cpp -I/usr/include/SDL -L/usr/lib/x86_64-linux-gnu -w -Wall -Wextra -std=c++17 -lSDL2 -o main
which worked but when I use it with mingw it doesn't i686-w64-mingw32-g++ main.cpp -I/usr/include/SDL -L/usr/lib/x86_64-linux-gnu -w -Wall -Wextra -std=c++17 -lSDL2 -o main
https://imgur.com/a/sF6CpcP
You need to include the path to SDL's include directory on the command line. However, you need to include the path to the downloaded SDL for mingw32, not /usr/include/SDL2. The difference is the headers in /usr/include/SDL2 are for Linux and libs in /usr/lib are also for Linux, but you need to link to the Windows libraries.
What I usually do is download the development libraries for Mingw32 and put them directly into my project directory. Then all you need to do is add -ISDL2-2.0.8/i686-w64-mingw32/include -LSDL2-2.0.8/i686-w64-mingw32/lib to your command line and it will be able to find the headers and libraries it needs. Finally, make sure you copy SDL2-2.0.8/i686-w64-mingw32/bin/SDL2.dll to your executable directory in the Makefile.
Also, remember to link SDLmain as well. It handles creating a WinMain for you and all that, and then calls your main function.

Running a SFML C++ program with minGW on Windows 10

So I'm trying to run an example SFML program on my Windows laptop. If relevant, the source code is on this page.
So first I make the .o file using this command -
g++ -c a.cpp -ISFML/SFML/include
Where a.cpp is the main file, and my SFML package is located in SFML/SFML.
Then I compile using this command -
g++ a.o -o a -LSFML/SFML/lib -lsfml-graphics -lsfml-window -lsfml-system
When I first ran the program I got the errors about not being able to find certain dlls, sfml-graphics-2 etc. So I found them and put them next to the exe. But now when I run, I get this weird error:
The procedure entry point
_ZNSt7__cxx1112basic_stringSt11char_traitsIcESalcEE7reserveEj could not be located in the dynamic link library.
What is going on here?
As the SFML download page states, You could be using the wrong version of the compiler, other library versions of SFML that you have not removed from your working directory that could mismatch between code and linker. Worst case, if your compiler is not listed there, you have to compile SFML yourself:
Get CMake. Get the source code for 2.4.2 by going to the bottom of the SFML download page. Follow this guide on SFML's GitHub repo. Alternatively, you could use the guide on SFML's page but it is for an older version. It might answer some questions that the first guide misses.
Ones CMake have generated the makefiles, you're on your way to build SFML.
Good luck!
I've had this problem for so long so I just wanted to help someone out who had the same problem. I have a windows 10 FYI and MinGW-w64 8.1.0 (if it doesnt work try a 32 bit mingw instead)
for a debug mode (debug is when your still working on the game and would like command prompt to open whenever you run it)
(make sure your in the right directory first by doing "cd")
g++ -c (file_name).cpp -o (file_name).o -I(path_to)SFML-64-bit/include -g -m64 -Wall &&
g++ (file_name).o -o (game_name).exe -L(path_to)SFML-64-bit/lib -lsfml-graphics -lsfml-window -lsfml-system
The code above when placed in command will compile everything for you if its all in the same directory so make sure you keep an eye out for that
and now for release mode (if you dont want command prompt to show up)
g++ -c (file_name).cpp -o (file_name).o -I(path_to)SFML-64-bit/include -O3 -m64 &&
g++ (file_name).o -o (game_name).exe -L(path_to)SFML-64-bit/lib -lsfml-graphics lsfml-window -lsfml-system -mwindows
Noticed all I added was the -mwindows and the -O3 aswell as removing -g and -Wall which are not necessary since we wont be using command prompt
Make sure to go to SFML/bin and take all the .dlls and put it into the same directory has your .exe sorry xd
Hope this helped.

Moxa PComm.lib with g++ under mingw64: file format not recognized

I am refactoring an old Borland C/C++98 program. I would like to program it under linux platform but to beginning, as I have severals additionnals boards, I clean the program, remove all GUI OWL and make tests under win7 and mingw64 to use modern gcc/g++.
I actually try to link a sample code that use C320 turbo Moxa multiport serial board.
As mentionned in
http://www.mingw.org/wiki/Specify_the_libraries_for_the_linker_to_use
it should link .lib and .dll.
So I tried to link my sample with Moxa PComm.lib for sio_open, sio_read, sio_write… functions as
g++ -m32 -Wall -std=c++14 src/main.cpp src/rs232_c320t.cpp … -L./lib -lPComm
and it returns
./lib/PComm.lib: file not recognized: File format not recognized
Are there any options to allow link windows .lib with gcc/g++ under mingw64?
Thanks
This related "Linking *.lib files with MinGW" question doesn't mention "File format not recognize" error. See also my comments below.
bcag2
I downloaded last PCommLite for win7 x64.
Copy C:\Program Files\Moxa\PCommLite 1.6\Include\PCOMM.H in my include project folder (lib in my case), and do the same for files PCOMM.dll and PCOMM.lib in C:\Program Files\Moxa\PCommLite 1.6\Lib\x64.
Then I compile with:
g++ -c -std=c++14 -D_hypot=hypot -DWIN32 src/*.cpp -I./lib/
Where -I./lib give access to PCOMM.H and link with:
g++ -shared *.o lib/PCOMM.LIB /c/Windows/System32/msvcr120.dll /c/ProgramData/Anaconda3/python36.dll -o _project.pyd
Of course you can do all in one time and create an .exe:
g++ -o project.exe -Wall -std=c++14 -DWIN32 src/*.cpp -Ilib/ lib/PCOMM.LIB -L./lib/
NO -ansi required as suggested by Moxa support!

Setting up Netbeans to compile wxWidgets projects under Windows

I'm trying to set up my Netbeans IDE so that it is capable of compiling wxWidgets projects.
There is very similar question:
Setup wxWidget in Netbeans 6.1 C++ On MS Windows?
but the answer is not working for me. And the mentioned versions are a bit outdated.
I use the mingw package for compilation.
There is no problem compiling a small hello World App from the console using this command in mysys:
$ g++ hello.cpp `wx-config --libs` `wx-config --cxxflags` -o hello.exe
So here's what I tried in Netbeans:
Project properties:
C++ Compiler -> Additional Options: wx-config cxxflags (surrounded by backticks)
C++ Compiler -> Include directories: installation_Path/include
Linker -> Additional Options: wx-config --libs (surrounded by backticks)
The command lines Netbeans creates when I try to compile seem to be correct to me
g++.exe `wx-config --cxxflags` -c -g -I/D/lib/wxWidgets/include -MMD -MP -MF build/Debug/MinGW-Windows/main.o.d -o build/Debug/MinGW-Windows/main.o main.cpp
This compiles without errors
g++.exe `wx-config --cxxflags` `wx-config --libs` -o dist/Debug/MinGW-Windows/wxwidgetstest build/Debug/MinGW-Windows/main.o -L/D/lib/wxWidgets/lib/gcc_lib
But during the linking process I get loads of errors...
Questions:
Does anybody have a working configuration for compiling wxWidgets Projects from within Netbeans and can help me out
Or does anybody see an error in the command lines could be the reason for the linking problems ?
Thank you very much!
I finally found the solution, and wrote a guide for anyone who might encounter the same problem in the future.
wxWidgets wiki: Compiling using Netbeans

-L option not working for mingw gcc

I am trying to get mingw gcc to work.
I need it to link with libopengl32.a.
Said file exists in C:/mingw/lib.
I used g++ as follows:
g++ -L"C:/mingw/lib" main.o -o test.exe -llibopengl32.a
It has no trouble finding the includes, it just complains that it can't find the library.
It seems unable to find any other library as well.
Also: I installed all the mingw components manually by downloading them from sourceforge, since using the automatic installer produced a broken installation on my system.
The -l flag automatically adds the lib prefix and the .a extension- you want:
g++ -LC:/mingw/lib main.o -o test.exe -lopengl32
Note you don't need the quotes around the path either. You could also just specify the whole library name & path:
g++ main.o -o test.exe C:/mingw/lib/libopengl32.a
As regards your installation problems, use either http://tdragon.net/recentgcc/ or http://nuwen.net/mingw.html - using the MinGW site itself is a recipe for pain.
You need to use -lopengl32 without "lib" and ".a"