I'm attempting to edit a big 'ol wind tunnel simulation to spit output files in the .hdf5 format rather than the current format, .CSV.
The entire simulation currently runs on Eclipse CDT, and is compiled & linked using MinGW g++ on a mix of Windows and Linux platforms; I am using a Windows 7 Enterprise device. My job is to edit a few lines of the simulation's source code to output files in the HDF5 format.
The problem is -- I can't get anything to link without a hodge-podge of "undefined reference" errors. I started out by using the HDF5 1.8.19 distributions for windows, but the included .lib + .dll files are specifically designed for the MSVS2013 compiler. I have since switched to using the Linux line endings due to g++ compatibility, but I still get a multitude of "undefined reference" errors.
I'm linking the libraries and include files, and I'm also linking their search paths. The issue seems to be that for some reason the MinGW linker can't read the symbol names in the libhdf5_cpp.a files.
Any thoughts? Does anyone have experience trying to interface eclipse with HDF5?
I'm just trying to run this example code.
My output errors are as follows:
g++ "-LC:\\Users\\jk5759\\workspace\\HDF5_Test" -o HDF5_Test.exe main.o -lhdf5_cpp -static
main.o: In function `main':
C:\Users\jk5759\workspace\HDF5_Test\Debug/../main.cpp:14: undefined reference to `H5check_version'
C:\Users\jk5759\workspace\HDF5_Test\Debug/../main.cpp:14: undefined reference to `H5Fcreate'
C:\Users\jk5759\workspace\HDF5_Test\Debug/../main.cpp:17: undefined reference to `H5Fclose'
collect2: ld returned 1 exit status
In general, C++ libraries have to be explicitly build for a specific target compiler due to name-mangling issues, differing binary specifications for exceptions, etc. Your best bet is probably going to be to build the HDF5 library from source using MinGW and use that.
See also here (MinGW docs).
I'm going to answer this question myself, because there simply isn't any resource on the web that really talks about using HDF5 + Windows + MinGW GCC + Eclipse.
Instructions for installing HDF5 for use with the following:
-Eclipse CDT Neon
-Windows 7 Enterprise
-C++ Programming
-MinGW GCC Compiler
1) Make certain you're logged in with admin privelages. MinGW and MSYS, as well as HDF5, may not install correctly without admin rights.
2) Obtain HDF5 version 1.8.2. This is available via the following URL: https://support.hdfgroup.org/ftp/HDF5/prev-releases/hdf5-1.8/hdf5-1.8.2/src/
Make sure to get the .tar version. This folder contains the source code only, which will still need to be edited in the future.
Unpack the tarball and move it to a directory where you can easily find it. Mine is labelled "MyHDFstuff", and is in the "Documents" folder.
Once the tarball is unpacked, find all files named H5pubconf.h and append the following lines to the end of the program:
There should be two H5pubconf.h files, one in the /src/ folder and one in the /windows/src/ folder.
/* ~~~~ User Added Code ~~~~ */
#ifndef H5_HAVE_WIN32_API
#ifdef WIN32 /* defined for all windows systems */
#define H5_HAVE_WIN32_API 1
#endif
#endif
#ifndef H5_HAVE_MINGW
#ifdef __MINGW32__ /*defined for all MinGW compilers */
#define H5_HAVE_MINGW 1
#endif
#endif
//fixes second problem
#define H5_BUILT_AS_DYNAMIC_LIB 1
3) Obtain MSYS linux command-line emulator for windows. This is a tool designed to interface with MinGW and provide Lunix-like utilities.
The ones of particular intrest to us are the "./configure", "make", and "make install" commands. It can be obtained here: http://www.mingw.org/wiki/MSYS
4) Launch MSYS. Navigate to the "MyHDFstuff" folder within MSYS using the "cd" command. Run the following commands from the MSYS prompt:
$ ./configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --disable-hl --prefix=$HOME
$ make
$ make check
$ make install
This will build the HDF5 libraries for the MinGW compiler. You should get an error -- ignore it, it's not going to stop your code from compiling and running.
5) In your eclipse project settings, make the following changes:
-add "hdf5-1.8.2\c++\src" to your include paths. this is most of the c++ utilities
-add "hdf5-1.8.2\src" to your include paths. This is most of the HDF5 C root utilities
-add "hdf5-1.8.2\src.libs" to your library folder search paths (-L)
-add "hdf5" to your libraries (-l)
** Note, this will not get you all the way to using the C++ API interface, but you will be able to program using the C commands (https://support.hdfgroup.org/HDF5/doc1.8/).
If these steps are not followed, then you will be able to use several of the C-interface commands, including file creation, but your executable will fail because it will be
unable to find the datatypes interface.
*** I will attach an example C++ program and output file in the future for reference
Happy coding!
Related
I want to make a game using SDL2, but I'm unable to compile and/or run my code, please help!
SDL2 is notoriously hard to set up, and it's often the first library aspiring game developers try to use.
This post is intended as a canonical duplicate for common problems with setting up SDL2.
This answer is about MinGW / GCC, and not Visual Studio.
This answer only applies to Windows.
Common errors
The common errors are:
SDL.h: No such file or directory (when compiling)
Various SDL_main problems: "undefined reference to SDL_main", "conflicting types for SDL_main" or "number of arguments doesn't match prototype", etc. (when compiling or linking)
undefined reference to other functions (when linking)
DLL problems: (when running your program)
'??.dll' was not found
procedure entry point ... could not be located in ..., and other mysterious DLL-related errors
The program seemingly doing nothing when launched
This list is sorted from bad to good. If you change something and get a different error, use this list to tell if you made things better or worse.
The preamble
0. Don't follow bad advice.
Some resources will suggest you to do #define SDL_MAIN_HANDLED or #undef main. Don't blindly follow that advice, it's not how SDL2 is intended to be used.
If you do everything correcty, it will never be necessary. Learn the intended approach first. Then you can research what exactly that does, and make an educated decision.
1. Figure out how to compile directly from the console, you can start using an IDE and/or build system later.
If you're using an IDE, I suggest to first make sure you're able to compile your program directly from the console, to rule out any IDE configuration problems. After you figure that out, you can use the same compiler options in your IDE.
The same applies to build systems, such as CMake.
2. Download the right SDL2 files. Make sure you have the right files. You need the archive called SDL2-devel-2.0.x-mingw.tar.gz from here.
Extract it to any directory, preferably somewhere near your source code. Extracting into the compiler installation directory is often considered a bad practice (and so is copying them to C:\Windows, which is a horrible idea).
3. Know the difference between compiler flags and linker flags. A "flag" is an option you specify in the command line when building your program. When you use a single command, e.g. g++ foo.cpp -o foo.exe, all your flags are added to the same place (to this single command).
But when you build your program in two steps, e.g.:
g++ foo.cpp -c -o foo.o (compiling)
g++ foo.o -o foo.exe (linking)
you have to know which of the two commands to add a flag to. Those are "compiler flags" and "linker flags" respectively.
Most IDEs will require you to specify compiler and linker flags separately, so even if you use a single command now, it's good to know which flag goes where.
Unless specified otherwise, the order of the flags doesn't matter.
SDL.h: No such file or directory
Or any similar error related to including SDL.h or SDL2/SDL.h.
You need to tell your compiler where to look for SDL.h. It's in the SDL files you've downloaded (see preamble).
Add -Ipath to your compiler flags, where path is the directory where SDL.h is located.
Example: -IC:/Users/HolyBlackCat/Downloads/SDL2-2.0.12/x86_64-w64-mingw32/include/SDL2. Relative paths work too, e.g. -ISDL2-2.0.12/x86_64-w64-mingw32/include/SDL2.
Note that the path will be different depending on how you write the #include:
If you do #include <SDL.h>, then the path should end with .../include/SDL2 (like above). This is the recommended way.
If you do #include <SDL2/SDL.h>, then the path should end with .../include.
Various SDL_main problems
You can get several different errors mentioning SDL_main, such as undefined reference to SDL_main, or conflicting types for 'SDL_main', or number of arguments doesn't match prototype, etc.
You need to have a main function. Your main function must look like int main(int, char **). NOT int main() and NOT void main(). This is a quirk of SDL2, related to it doing #define main SDL_main.
Adding parameter names is allowed (and is mandatory in C), e.g. int main(int argc, char **argv). Also the second parameter can be written as char *[] or with a name: char *argv[]. No other changes are allowed.
If your project has multiple source files, make sure to include SDL.h in the file that defines the main function, even if it doesn't otherwise use SDL directly.
Try to avoid #define SDL_MAIN_HANDLED or #undef main when solving this issue, see preamble for explanation.
undefined reference to various functions
• undefined reference to SDL_...
The error message will mention various SDL_... functions, and/or WinMain. If it mentions SDL_main, consult the section "Various SDL_main problems" above. If the function names don't start with SDL_, consult the section "undefined reference to other functions" below.
You need to add following linker flags: -lmingw32 -lSDL2main -lSDL2 -Lpath, where path is the directory where libSDL2.dll.a and libSDL2main.a (which you've downloaded) are located. The order of the -l... flags matters. They must appear AFTER any .c/.cpp/.o files.
Example: -LC:/Users/HolyBlackCat/Desktop/SDL2-2.0.12/x86_64-w64-mingw32/lib. Relative paths work too, e.g. -LSDL2-2.0.12/x86_64-w64-mingw32/lib.
When you use -l???, the linker will look for a file called lib???.dll.a or lib???.a (and some other variants), which is why we need to pass the location of those files. libmingw32.a (corresponding to -lmingw32) is shipped with your compiler, so it already knows where to find it.
I added all those flags and nothing changed, or I'm getting skipping incompatible X when searching for Y:
You probably use the wrong SDL .a files. The archive you downloaded contains two sets of files: i686-w64-mingw32 (32-bit) and x86_64-w64-mingw32 (64-bit). You must use the files matching your compiler, which can also be either 32-bit or 64-bit.
Print (8*sizeof(void*)) to see if your compiler is 32-bit or 64-bit.
Even if you think you use the right files, try the other ones to be sure.
Some MinGW versions can be switched between 32-bit and 64-bit modes using -m32 and -m64 flags (add them to both compiler and linker flags).
I get undefined reference to a specific function:
• undefined reference to WinMain only
There are several possibilities, all of which were covered in the previous section:
You forgot -lmingw32 and/or -lSDL2main linker flags.
You must use following linker flags, in this exact order, after
any .c/.cpp/.o files: -lmingw32 -lSDL2main -lSDL2
The libSDL2main.a file you use doesn't match your compiler (32-bit file with a 64-bit compiler, or vice versa).
Try to avoid #define SDL_MAIN_HANDLED or #undef main when solving this issue, see preamble for explanation.
• undefined reference to SDL_main only
See the section "Various SDL_main problems" above.
• undefined reference to other functions
Your linker found and used libSDL2.a, but it should be finding and using libSDL2.dll.a. When both are available, it prefers the latter by default, meaning you didn't copy the latter to the directory you passed to -L.
If you intended to perform static linking, see the section called "How do I distribute my app to others?" below.
Nothing happens when I try run my app
Let's say you try to run your app, and nothing happens. Even if you try to print something at the beginning of main(), it's not printed.
Windows has a nasty habit of not showing some DLL-related errors when the program is started from the console.
If you were running your app from the console (or from an IDE), instead try double-clicking the EXE in the explorer. Most probably you'll now see some DLL-related error; then consult one of the next sections.
??.dll was not found
Copy the .dll mentioned in the error message, and place it next to your .exe.
If the DLL is called SDL2.dll, then it's in the SDL files you've downloaded (see preamble). Be aware that there are two different SDL2.dlls: a 32-bit one (in the i686-w64-mingw32 directory), and a 64-bit one (in x86_64-w64-mingw32). Get the right one, if necessary try both.
Any other DLLs will be in your compiler's bin directory (the directory where gcc.exe is located).
You might need to repeat this process 3-4 times, this is normal.
For an automatic way of determining the needed DLLs, see the next section.
procedure entry point ... could not be located in ... and other cryptic DLL errors
Your program needs several .dlls to run, and it found a wrong version of one, left over from some other program you have installed.
It looks for DLLs in several different places, but the directory with the .exe has the most priority.
You should copy all DLLs your program uses (except the system ones) into the directory where your .exe is located.
A reliable way to get a list of needed DLLs is to blindly copy a bunch of DLLs, and then remove the ones that turn out to be unnecessary:
Copy SDL2.dll. It's in the SDL files you've downloaded (see preamble). Be aware that there are two different SDL2.dlls: a 32-bit one (in the i686-w64-mingw32 directory), and a 64-bit one (in x86_64-w64-mingw32). Get the right one, if necessary try both.
Copy all DLLs from your compiler's bin directory (the directory where gcc.exe is located).
Now your program should run, but we're not done yet.
Download NTLDD (or some other program that displays a list of used DLLs). Run ntldd -R your_program.exe.
Any DLL not mentioned in its output should be removed from the current directory. Your program uses everything that remains.
I ended up with following DLLs, expect something similar: SDL2.dll, libgcc_s_seh-1.dll, libstdc++-6.dll (C++ only), libwinpthread-1.dll.
Can I determine the needed DLLs without copying excessive ones?
Yes, but it's less reliable.
Your program searches for DLLs in following locations, in this order:
The directory where your .exe is located.
C:\Windows, including some of its subdirectories.
The directories listed in PATH.
Assuming you (or some jank installer) didn't put any custom DLLs into C:\Windows, adding your compiler's bin directory to the PATH (preferably as the first entry) and either putting SDL2.dll in the same directory as the .exe or into some directory in the PATH should be enough for your program to work.
If this works, you can then run ntldd without copying any DLLs beforehand, and copy only the necessary ones. The reason why you'd want to copy them at all at this point (since your app already works) is to be able to distribute it to others, without them having to install the compiler for its DLLs. Skip any DLLs located outside of your compiler's bin directory (except for SDL2.dll).
Note that the possibility of having weird DLLs in C:\Windows is real. E.g. Wine tends to put OpenAL32.dll into C:\Windows, so if you try this process with OpenAL on Wine, it will fail. If you're making a sciprt that runs ntldd automatically, prefer copying the DLLs (or at least symlinking them - I heard MSYS2 can emulate symlinks on Windows?).
Can I make an EXE that doesn't depend on any DLLs?
It's possible to make an .exe that doesn't depend on any (non-system) .dlls by using the -static linker flag, this is called "static linking". This is rarely done, and you shouldn't need to do this if you did the above steps correctly. This requires some additional linker flags; they are listed in file ??-w64-mingw32/lib/pkgconfig/sdl2.pc shipped with SDL, in the Libs.private section. Notice that there are two files, for x32 and x64 respectively.
How do I distribute my app to others?
Follow the steps in the previous section, titled procedure entry point ... could not be located in ....
A saner alternative?
There is MSYS2.
It has a package manager that lets you download prebuilt libraries, and, as a bonus, a fresh version of the compiler.
Install SDL2 from its package manager. Use a tool called pkg-config (also from the package manager) to automatically determine all necessary flags (pkg-config --cflags SDL2 for compiler flags, pkg-config --libs SDL2 for linker flags).
This is the same experience as you would have on Linux (maybe except for some DLL management hassle).
Bonus - Other problems
Q: My program always opens a console window when I run it, how do I hide it?
A: Add -mwindows to the linker flags.
Q: I get error 'SDL_VideoMode' wasn't declared in this scope.
A: SDL_VideoMode is from SDL1.2, it's not a part of the newer SDL2. Your code was written for the outdated version of SDL. Find a better tutorial that deals specifically with SDL2.
Q: My program has the default file icon, but I want a custom one.
A: Your icon must be in the .ico format. If your graphics editor doesn't support it, make a series of .pngs of common sizes (e.g. 16x16, 32x32, 48x48, 64x64), then convert them to a single .ico using ImageMagick: magick *.png result.ico (or with convert instead of magick).
Create a file with the .rc extension (say, icon.rc), with following contents MyIconName ICON "icon.ico" (where MyIconName is an arbitrary name, and "icon.ico" is the path to the icon). Convert the file to an .o using windres -O res -i icon.rc -o icon.o (the windres program is shipped with your compiler). Specify the resulting .o file when linking, e.g. g++ foo.cpp icon.o -o foo.exe.
Recent versions of SDL2 have a nice property of using the same icon as the window icon, so you don't have to use SDL_SetWindowIcon.
A solution for Visual Studio:
Why not use a package manager? I use vcpkg, and it makes super easy to consume 3rd party libraries. Grab the vcpkg source, and extract it to a safe place, like C:/, then run its bootstrap script bootstrap-vcpkg.bat, this will generate vcpkg executable. Then run vcpkg integrate install to make libraries installed with vcpkg available in Visual Studio.
Search for the library you need:
vcpkg search sdl
imgui[sdl2-binding] Make available SDL2 binding
libwebp[vwebp-sdl] Build the vwebp viewer tool.
magnum[sdl2application] Sdl2Application library
sdl1 1.2.15#12 Simple DirectMedia Layer is a cross-platform development library designed to p...
sdl1-net 1.2.8-3 Networking library for SDL
sdl2 2.0.12-1 Simple DirectMedia Layer is a cross-platform
...
Install it with: vcpkg install sdl2.
Now you just need include SDL2 headers, and everything will work out of the box. The library will be linked automatically.
You can learn more about vcpkg here.
On Mac this is what I follow for XCode (must install g++):
sdl linking:
g++ main.cpp -o main $(sdl2-config --cflags --libs)
XCODE project steps:
open terminal app (macOS)
BUILD SETTINGS (select 'all' and 'combined' search bar enter: "search")
click on "header search paths(way right side click)
add: /usr/local/include
BUILD PHASES --> LINK BINARY LIBRARIES (click plus)
type in SDL --> click "add other"
press: command+SHIFT+g (to bring search bar)
type in: usr/local/Cellar
navigate to: SDL2 -->2.0.8 -->lib --> libSDL2-2.2.0.dylib (make sure not shortcut)
I want to make a game using SDL2, but I'm unable to compile and/or run my code, please help!
SDL2 is notoriously hard to set up, and it's often the first library aspiring game developers try to use.
This post is intended as a canonical duplicate for common problems with setting up SDL2.
This answer is about MinGW / GCC, and not Visual Studio.
This answer only applies to Windows.
Common errors
The common errors are:
SDL.h: No such file or directory (when compiling)
Various SDL_main problems: "undefined reference to SDL_main", "conflicting types for SDL_main" or "number of arguments doesn't match prototype", etc. (when compiling or linking)
undefined reference to other functions (when linking)
DLL problems: (when running your program)
'??.dll' was not found
procedure entry point ... could not be located in ..., and other mysterious DLL-related errors
The program seemingly doing nothing when launched
This list is sorted from bad to good. If you change something and get a different error, use this list to tell if you made things better or worse.
The preamble
0. Don't follow bad advice.
Some resources will suggest you to do #define SDL_MAIN_HANDLED or #undef main. Don't blindly follow that advice, it's not how SDL2 is intended to be used.
If you do everything correcty, it will never be necessary. Learn the intended approach first. Then you can research what exactly that does, and make an educated decision.
1. Figure out how to compile directly from the console, you can start using an IDE and/or build system later.
If you're using an IDE, I suggest to first make sure you're able to compile your program directly from the console, to rule out any IDE configuration problems. After you figure that out, you can use the same compiler options in your IDE.
The same applies to build systems, such as CMake.
2. Download the right SDL2 files. Make sure you have the right files. You need the archive called SDL2-devel-2.0.x-mingw.tar.gz from here.
Extract it to any directory, preferably somewhere near your source code. Extracting into the compiler installation directory is often considered a bad practice (and so is copying them to C:\Windows, which is a horrible idea).
3. Know the difference between compiler flags and linker flags. A "flag" is an option you specify in the command line when building your program. When you use a single command, e.g. g++ foo.cpp -o foo.exe, all your flags are added to the same place (to this single command).
But when you build your program in two steps, e.g.:
g++ foo.cpp -c -o foo.o (compiling)
g++ foo.o -o foo.exe (linking)
you have to know which of the two commands to add a flag to. Those are "compiler flags" and "linker flags" respectively.
Most IDEs will require you to specify compiler and linker flags separately, so even if you use a single command now, it's good to know which flag goes where.
Unless specified otherwise, the order of the flags doesn't matter.
SDL.h: No such file or directory
Or any similar error related to including SDL.h or SDL2/SDL.h.
You need to tell your compiler where to look for SDL.h. It's in the SDL files you've downloaded (see preamble).
Add -Ipath to your compiler flags, where path is the directory where SDL.h is located.
Example: -IC:/Users/HolyBlackCat/Downloads/SDL2-2.0.12/x86_64-w64-mingw32/include/SDL2. Relative paths work too, e.g. -ISDL2-2.0.12/x86_64-w64-mingw32/include/SDL2.
Note that the path will be different depending on how you write the #include:
If you do #include <SDL.h>, then the path should end with .../include/SDL2 (like above). This is the recommended way.
If you do #include <SDL2/SDL.h>, then the path should end with .../include.
Various SDL_main problems
You can get several different errors mentioning SDL_main, such as undefined reference to SDL_main, or conflicting types for 'SDL_main', or number of arguments doesn't match prototype, etc.
You need to have a main function. Your main function must look like int main(int, char **). NOT int main() and NOT void main(). This is a quirk of SDL2, related to it doing #define main SDL_main.
Adding parameter names is allowed (and is mandatory in C), e.g. int main(int argc, char **argv). Also the second parameter can be written as char *[] or with a name: char *argv[]. No other changes are allowed.
If your project has multiple source files, make sure to include SDL.h in the file that defines the main function, even if it doesn't otherwise use SDL directly.
Try to avoid #define SDL_MAIN_HANDLED or #undef main when solving this issue, see preamble for explanation.
undefined reference to various functions
• undefined reference to SDL_...
The error message will mention various SDL_... functions, and/or WinMain. If it mentions SDL_main, consult the section "Various SDL_main problems" above. If the function names don't start with SDL_, consult the section "undefined reference to other functions" below.
You need to add following linker flags: -lmingw32 -lSDL2main -lSDL2 -Lpath, where path is the directory where libSDL2.dll.a and libSDL2main.a (which you've downloaded) are located. The order of the -l... flags matters. They must appear AFTER any .c/.cpp/.o files.
Example: -LC:/Users/HolyBlackCat/Desktop/SDL2-2.0.12/x86_64-w64-mingw32/lib. Relative paths work too, e.g. -LSDL2-2.0.12/x86_64-w64-mingw32/lib.
When you use -l???, the linker will look for a file called lib???.dll.a or lib???.a (and some other variants), which is why we need to pass the location of those files. libmingw32.a (corresponding to -lmingw32) is shipped with your compiler, so it already knows where to find it.
I added all those flags and nothing changed, or I'm getting skipping incompatible X when searching for Y:
You probably use the wrong SDL .a files. The archive you downloaded contains two sets of files: i686-w64-mingw32 (32-bit) and x86_64-w64-mingw32 (64-bit). You must use the files matching your compiler, which can also be either 32-bit or 64-bit.
Print (8*sizeof(void*)) to see if your compiler is 32-bit or 64-bit.
Even if you think you use the right files, try the other ones to be sure.
Some MinGW versions can be switched between 32-bit and 64-bit modes using -m32 and -m64 flags (add them to both compiler and linker flags).
I get undefined reference to a specific function:
• undefined reference to WinMain only
There are several possibilities, all of which were covered in the previous section:
You forgot -lmingw32 and/or -lSDL2main linker flags.
You must use following linker flags, in this exact order, after
any .c/.cpp/.o files: -lmingw32 -lSDL2main -lSDL2
The libSDL2main.a file you use doesn't match your compiler (32-bit file with a 64-bit compiler, or vice versa).
Try to avoid #define SDL_MAIN_HANDLED or #undef main when solving this issue, see preamble for explanation.
• undefined reference to SDL_main only
See the section "Various SDL_main problems" above.
• undefined reference to other functions
Your linker found and used libSDL2.a, but it should be finding and using libSDL2.dll.a. When both are available, it prefers the latter by default, meaning you didn't copy the latter to the directory you passed to -L.
If you intended to perform static linking, see the section called "How do I distribute my app to others?" below.
Nothing happens when I try run my app
Let's say you try to run your app, and nothing happens. Even if you try to print something at the beginning of main(), it's not printed.
Windows has a nasty habit of not showing some DLL-related errors when the program is started from the console.
If you were running your app from the console (or from an IDE), instead try double-clicking the EXE in the explorer. Most probably you'll now see some DLL-related error; then consult one of the next sections.
??.dll was not found
Copy the .dll mentioned in the error message, and place it next to your .exe.
If the DLL is called SDL2.dll, then it's in the SDL files you've downloaded (see preamble). Be aware that there are two different SDL2.dlls: a 32-bit one (in the i686-w64-mingw32 directory), and a 64-bit one (in x86_64-w64-mingw32). Get the right one, if necessary try both.
Any other DLLs will be in your compiler's bin directory (the directory where gcc.exe is located).
You might need to repeat this process 3-4 times, this is normal.
For an automatic way of determining the needed DLLs, see the next section.
procedure entry point ... could not be located in ... and other cryptic DLL errors
Your program needs several .dlls to run, and it found a wrong version of one, left over from some other program you have installed.
It looks for DLLs in several different places, but the directory with the .exe has the most priority.
You should copy all DLLs your program uses (except the system ones) into the directory where your .exe is located.
A reliable way to get a list of needed DLLs is to blindly copy a bunch of DLLs, and then remove the ones that turn out to be unnecessary:
Copy SDL2.dll. It's in the SDL files you've downloaded (see preamble). Be aware that there are two different SDL2.dlls: a 32-bit one (in the i686-w64-mingw32 directory), and a 64-bit one (in x86_64-w64-mingw32). Get the right one, if necessary try both.
Copy all DLLs from your compiler's bin directory (the directory where gcc.exe is located).
Now your program should run, but we're not done yet.
Download NTLDD (or some other program that displays a list of used DLLs). Run ntldd -R your_program.exe.
Any DLL not mentioned in its output should be removed from the current directory. Your program uses everything that remains.
I ended up with following DLLs, expect something similar: SDL2.dll, libgcc_s_seh-1.dll, libstdc++-6.dll (C++ only), libwinpthread-1.dll.
Can I determine the needed DLLs without copying excessive ones?
Yes, but it's less reliable.
Your program searches for DLLs in following locations, in this order:
The directory where your .exe is located.
C:\Windows, including some of its subdirectories.
The directories listed in PATH.
Assuming you (or some jank installer) didn't put any custom DLLs into C:\Windows, adding your compiler's bin directory to the PATH (preferably as the first entry) and either putting SDL2.dll in the same directory as the .exe or into some directory in the PATH should be enough for your program to work.
If this works, you can then run ntldd without copying any DLLs beforehand, and copy only the necessary ones. The reason why you'd want to copy them at all at this point (since your app already works) is to be able to distribute it to others, without them having to install the compiler for its DLLs. Skip any DLLs located outside of your compiler's bin directory (except for SDL2.dll).
Note that the possibility of having weird DLLs in C:\Windows is real. E.g. Wine tends to put OpenAL32.dll into C:\Windows, so if you try this process with OpenAL on Wine, it will fail. If you're making a sciprt that runs ntldd automatically, prefer copying the DLLs (or at least symlinking them - I heard MSYS2 can emulate symlinks on Windows?).
Can I make an EXE that doesn't depend on any DLLs?
It's possible to make an .exe that doesn't depend on any (non-system) .dlls by using the -static linker flag, this is called "static linking". This is rarely done, and you shouldn't need to do this if you did the above steps correctly. This requires some additional linker flags; they are listed in file ??-w64-mingw32/lib/pkgconfig/sdl2.pc shipped with SDL, in the Libs.private section. Notice that there are two files, for x32 and x64 respectively.
How do I distribute my app to others?
Follow the steps in the previous section, titled procedure entry point ... could not be located in ....
A saner alternative?
There is MSYS2.
It has a package manager that lets you download prebuilt libraries, and, as a bonus, a fresh version of the compiler.
Install SDL2 from its package manager. Use a tool called pkg-config (also from the package manager) to automatically determine all necessary flags (pkg-config --cflags SDL2 for compiler flags, pkg-config --libs SDL2 for linker flags).
This is the same experience as you would have on Linux (maybe except for some DLL management hassle).
Bonus - Other problems
Q: My program always opens a console window when I run it, how do I hide it?
A: Add -mwindows to the linker flags.
Q: I get error 'SDL_VideoMode' wasn't declared in this scope.
A: SDL_VideoMode is from SDL1.2, it's not a part of the newer SDL2. Your code was written for the outdated version of SDL. Find a better tutorial that deals specifically with SDL2.
Q: My program has the default file icon, but I want a custom one.
A: Your icon must be in the .ico format. If your graphics editor doesn't support it, make a series of .pngs of common sizes (e.g. 16x16, 32x32, 48x48, 64x64), then convert them to a single .ico using ImageMagick: magick *.png result.ico (or with convert instead of magick).
Create a file with the .rc extension (say, icon.rc), with following contents MyIconName ICON "icon.ico" (where MyIconName is an arbitrary name, and "icon.ico" is the path to the icon). Convert the file to an .o using windres -O res -i icon.rc -o icon.o (the windres program is shipped with your compiler). Specify the resulting .o file when linking, e.g. g++ foo.cpp icon.o -o foo.exe.
Recent versions of SDL2 have a nice property of using the same icon as the window icon, so you don't have to use SDL_SetWindowIcon.
A solution for Visual Studio:
Why not use a package manager? I use vcpkg, and it makes super easy to consume 3rd party libraries. Grab the vcpkg source, and extract it to a safe place, like C:/, then run its bootstrap script bootstrap-vcpkg.bat, this will generate vcpkg executable. Then run vcpkg integrate install to make libraries installed with vcpkg available in Visual Studio.
Search for the library you need:
vcpkg search sdl
imgui[sdl2-binding] Make available SDL2 binding
libwebp[vwebp-sdl] Build the vwebp viewer tool.
magnum[sdl2application] Sdl2Application library
sdl1 1.2.15#12 Simple DirectMedia Layer is a cross-platform development library designed to p...
sdl1-net 1.2.8-3 Networking library for SDL
sdl2 2.0.12-1 Simple DirectMedia Layer is a cross-platform
...
Install it with: vcpkg install sdl2.
Now you just need include SDL2 headers, and everything will work out of the box. The library will be linked automatically.
You can learn more about vcpkg here.
On Mac this is what I follow for XCode (must install g++):
sdl linking:
g++ main.cpp -o main $(sdl2-config --cflags --libs)
XCODE project steps:
open terminal app (macOS)
BUILD SETTINGS (select 'all' and 'combined' search bar enter: "search")
click on "header search paths(way right side click)
add: /usr/local/include
BUILD PHASES --> LINK BINARY LIBRARIES (click plus)
type in SDL --> click "add other"
press: command+SHIFT+g (to bring search bar)
type in: usr/local/Cellar
navigate to: SDL2 -->2.0.8 -->lib --> libSDL2-2.2.0.dylib (make sure not shortcut)
I am trying to install QuantLib on my Mac running OSX 10.11.6. Installed Boost 1.59 via MacPorts and then followed these instructions.
I used these additional environment variables
./configure --with-boost-include=/opt/local/include/ \
--with-boost-lib=/opt/local/lib/ --prefix=/opt/local/ \
CXXFLAGS='-O2 -stdlib=libstdc++ -mmacosx-version-min=10.6' \
LDFLAGS='-stdlib=libstdc++ -mmacosx-version-min=10.6'
and then make && sudo make install.
However when I run the Bermuda Swaption test it gave me the same error described here.
Little premise: I don't know anything about C++. I need QuantLib to work on Python. So I read carefully the answer by SmallChess and tried to solve it by myself. As I read in his answer
You can't just compile BermudanSwaption.cpp and hope everything would be fine. You have to compile the entire QuantLib library and link with the generated library files. Please google "compiling and linking C++" for more information.
By far, the easiest way to make it happen on Mac is to do it with Xcode. You will need to create a new Xcode project, and import the entire Quantlib project files into it. Next, you will need to create a main() function. Xcode does the compiling and linking for your automatically.
This is what I exactly did:
created a new project in Xcode (version 8.2.1)(file/new project/Command Line Tool/"HelloWorld"/Documents/create)
selected Targets, Build Phases and Link Binary With Library. Added libQuantLib.0.dylib
set libstdc++(GNUC++ standard library) as C++ Standard Library in Build Settings
Modified Header Search Paths to include: /opt/local/include/, and Library Search Paths to include: /opt/local/lib
C++ Language Dialect is set on Compiler Default.
Dragged the ql folder onto the left window of the Xcode
Now, I managed to copy a simple code which includes the library and even if there are many warnings, it runs. Still when I run on the Terminal the command for the Bermuda Swaption test I get the same error. What am I doing wrong?
Additional info (may or may not be useful): if I change the C++ Standard Library setting on Xcode to libc++, I get on Xcode the same error I get when i try the Bermuda Swaption test (ld: symbol(s) not found for architecture x86_64).
Any help would be very much appreciated
Regards
EDIT: you can find a picture of the code at https://i.stack.imgur.com/1zhjO.png
im trying to port a c++ project from visual studio 2013 to netbeans on ubuntu. The target is a windows executable, so far im able to compile windows exe files from netbeans using mingw as compiler.
The project needs the Crypto++ library and i only have the .lib version for visual studio. To include the library in netbeans i first need to build the Crypto++ library in the .a format.
Its not clear to me how should i do that.
Ive found informations on how to build the library for linux with mingw but not for cross compilation with mingw. The provided GNUmakefile does not work.
Should i set up a vm with windows and mingw and compile the library that way? Or maybe use the qmake "hack" as suggested here http://www.qtcentre.org/threads/28809-Compiling-amp-using-Crypto-with-mingw-version-of-Qt ? The last good Crypto++ version suggested there is quite old. This is confusing, porting the whole project is easier than having the required library.
Im open to any suggestion.
tldr: how to build libcryptopp.a on linux for the cross compilation of a windows exe project
edit:
for example if i cross compile something there are windows libraries in the /usr/i686-w64-mingw32/lib/ folder like libuser32.a. i need to make the equivalend libcryptopp.a.. sorry if is a bit unclear.
if i simply build using the steps in answer (and in the wiki) i end up with a libcryptopp.a file but i suspect is linux-only, cause if i link that library in netbeans in the .exe file im cross compiling i end up with undefined references to cryptopp stuff everywere. the paths are correct, i suspect the library needs to be replaced with the equivalent libcryptopp.a compatible with crosscompiling.
edit2: im trying to follow the answer down here, now im stuck here. after this command to build cryptopp.
make CXX=/usr/bin/i686-w64-mingw32-gcc INCLUDES="-I /usr/i686-w64-mingw32/include" LIBS="-L /usr/i686-w64-mingw32/lib" CXXFLAGS="-std=c++0x"
and many variations of it i always end up with this error
trap.h:26:25: fatal error: Windows.h: No such file or directory
# include
which makes me think its using the right compiler to make a .a lib file for cross compiling the windows .exe with the lib.
however i dont understand whats going on now with the missing header..:(
Also if i try to link the lib file (used with visual studio) i get a lot of linking errors, undefined reference to cryptopp stuff.
ill offer a symbolic beer (a couple of $ of Bitcoins) if someone finds out how to do it.
Inspired by http://wiki.amule.org/wiki/Cross-compilation_for_windows_with_mingw:
sudo apt-get install mingw-w64
git clone https://github.com/weidai11/cryptopp
cd cryptopp
export TARGET=i686-w64-mingw32
CXX=$TARGET-g++ RANLIB=$TARGET-ranlib AR=$TARGET-ar LDLIBS=-lws2_32 make -f GNUmakefile
I've found informations on how to build the library for linux with mingw but not for cross compilation with mingw.
Its relatively easy...
Get Crypto++ ZIP into MinGW.
Unpack Crypto++ ZIP.
Change directories.
Build the library.
Verify All tests passed.
(1) and (2) can be tricky because Cygwin and MinGW are missing a lot of tools. So curl https://www.cryptopp.com/cryptopp563.zip -o cryptopp563.zip may not work.
For (2), I seem to recall ZIP is missing, so unzip -aoq cryptopp563.zip -d cryptopp-5.6.3 may not work.
At step (4), just perform make static dynamic test and be sure it finished with All tests passed.
I do a lot of testing with Cygwin and MinGW. I have a script that copies Crypto++ into the environments from my Desktop. I have not been able to figure out a way to automate it. A recent question on automating it was closed, so no one can supply an answer (see How to automate software testing for Cygwin and MinGW).
C++-Protobuf does not compile in VS2012. Now I want to use MinGW to compile it on windows. Can someone please give me some brief headwords on how to compile protobuf on Win7 x64. I already installed MinGW with the GUI installer. Google writes as MinGW setup notice that I should refer to the Unix installation notes. But I cant figure out how to use the auto tools on windows.
Edit
Okay this is what I've done until now:
$ mount C:/ WinDir
$ cd ./[...]/protobuf.2.4.1
$ ./configure
$ minGW32-make.exe
$ minGW32-make.exe check
minGW32-make.exe runs without errors, but no tests are running and I cant find libprotobuf.lib. There are some libprotobuf.dll but I need the lib, dont I?.
You should have an MSys console together with your MinGW instalation. This console provides an linux-like environment in which you should be able to use autotools normally.
If MSys is not installed, you can grab it from the MinGW site too.
cd to your directory with sources and try the usual:
$ ./configure
$ make
Some libraries cause problems on Windows but most compile well with MinGW and MSys. Come back and add more info to your question if you run into specific problems.
Edit:
minGW32-make.exe runs without errors, but no tests are running and I cant find libprotobuf.lib. There are some libprotobuf.dll but I need the lib, dont I?.
Usually for a dynamic library you'd get protobuf.dll (the dynamic library) and libprotobuf.a (the static wrapper library).
When linking, just pass -lprotobuf to the linker - it will look for both libprotobuf.a and protobuf.lib.
(.lib is another static library format, which is partially handled by MinGW but not native here.)
You will not work with a .lib file when using the MinGW toolchain. Instead, you are able to link against the dll directly. The MinGW Wiki explains this.
I could get dll and lib both. This is when you do not want static lib file and want to use dll and lib file.
You need to make following changes in Protobuf code:
Open the project in VS. Or any other editor. I use VS2015.
In libProtoBuf project settings, in C/C++ Preprocessor add following flags.
PROTOBUF_USE_DLLS; LIBPROTOBUF_EXPORTS;
Those flags will export information from profobuf using dllexport
in ur client code where you are using Protobuf, define: PROTOBUF_USE_DLLS. Which will make protobuf includes to use dllimport.
Once you do step 2, you will see both dll and lib in your output folder. Otherwise, you will always see just dll and not lib file.
Hope this helps. If not, please write a message here and I can help you getting this sorted out.