I'm currently trying to write an app for Raspberry Pi 3B under Rasbpian with aid of Linux Development plugin in Visual Studio 2017 Community. I managed to successfully deploy 'Blink' example, nobly attached by Microsoft folks, according to tutorial, and that went well. I even made some transmission over SPI thanks to wiringPi library. Then I would like to add some GUI to my app, so that one could, for example, make some transmission on click of a button on screen.
IntelliSense hinted me, that, in fact, there is gtk-3.0 library present in toolset. It seems that libraries are being copied from target device on every connection or so and I installed gtk on my Raspberry. So I added a simple line to this Blink example:
#include <gtk-3.0/gtk/gtk.h>
On compilation attempt, of course there was nearly 4k errors. Well, enough said, with a little hint from this old tutorial and a bit of trial and error, I managed to add this set of links under Debugging/Project properties/Configuration properties/VC++ directories/Header files directories:
Everything goes in promising direction, as errors number diminished from 4k to just one:
gtk-3.0\gtk\gtk.h: No such file or directory
No matter that this file is ACTUALLY in this location:
Regardless of combination of links in configuration above and using statement composition, compiler (?) can't find this damn file.
Please Halp
EDIT
I just confirmed, that it is indeed problem with target configuration. This is bad or good, depending on point of view. Good, because there is probably all good with VS setup. Bad, because I don't know a thing about compiling things under Linux.
On target (Raspberry Pi 3B) all ingredients for compilation are copied by Linux Development plugin. So in Terminal I executed line:
g++ main.cpp -o Blink2onRPi
and got
main.cpp:4:21: fatal error: gtk/gtk.h: no such file or directory
Now, I altered include line in main.cpp on target RPi, to this:
#include <gtk-3.0/gtk/gtk.h>
And now its missing <gdk/gdk.h>! When this change is made on host windows device - same result, but in VS.
As I dealt with similar problem in VS, upon setting links for IntelliSense (now apparently they're for this purpose), now probably similar dependencies have to be set somewhere on Raspbian. But where?
EDIT2
Upon execution of:
g++ main.cpp -o Blink2onRPi `pkg-config --cflags --libs gtk+-3.0`
on target RPi there is no more GTK-related errors, just wiringPi (also present in project) undefined references. It raises two possible questions:
1) How can I setup wiringPi on RPi so that the project could be manually compiled on target and
2) How/where add above line to Visual Studio, so it execute remotely with all GTK dependencies added properly on target
Researching stock present wiringPi library (as this is Blink led example for cross-compile Linux Development) I've found, that in Project Properties/Linker/Input/Library Dependencies there is mysterious entry:
wiringPi
Just that, nothing more. After removing this entry, on compilation pops out same errors as before on target (which apparently lacks proper wiringPi setup) - undefined references (not mensioned any missing headers). Can this be relevant for the case? If so, how could I add there such entry which would deal with missing GTK dependencies?
TL;DR
Use screenshot below to know where to add pkg-config calls in VS configuration so that it forwards it to the compiler and linker on the target.
Thanks to #zaguoba for providing these.
ORIGINAL ANSWER:
The list of directories to include is provided by pkg-config. For example pkg-config --cflags-only-I gtk+-3.0 will give you the list of include directories required. Those are the ones you need to add to the directories where VC++ wil look at include files. If you add the relative path you use in the #include, to one of those paths, you are able to find the file.
Example:
If you add to the directories C:\Program Files\foo\bar\gtk+-3.0
and have in your C file:
#include <gtk/gtk.h>
then the compiler will look for C:\Program Files\foo\bar\gtk+-3.0\gtk\gtk.h.
EDIT:
This all means the 'file not found' errors are because you're really building on the target and the target has no idea what C:\Program Files\... means. Those should be paths on the target filesystem, where the compiler is called. And this is exactly what pkg-config provides.
The copy of those files on the Windows machine filesystems is merely for Intellisense use, not for compiler use.
EDIT 2:
So that's that Visual Studio 2017 Community Linux Development plugin is what need to be undestood. It's not for cross compilation from Windows to Linux, istead it merely synchronizes code to the Windows host (for Intellisense use), but builds on the target. This means that all the paths and commands are Linux paths and commands, run on the target.
Here's the OP working configuration:
With that setup, you should
#include <gtk\gtk.h>
instead of
#include <gtk-3.0\gtk\gtk.h>
Alternatively remove all those VC++ directories/Header files directories, and just keep one of them that ends with include/ instead of listing up all the sub directiores.
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)
There are various Go libraries that rely on the cuda.h file and the cuda library (specifically ML libraries). Every time I try to install one of these libraries on Windows, I get an error saying
fatal error: cuda.h: No such file or directory
//#include <cuda.h>
I am aware of what I need to do (link the Cuda library/header files to the go library that I am trying to install), however, I am not sure how to go about doing this especially on windows. I am using GCC and not MSVC for various reasons, but even when I've tried using MSVC, I've had the same issues.
Is there some way that I can link the cuda compiler/header files directly to my Go env or do I need to manually point the go/cgo compiler to the directory holding the Cuda headers and how do I go about doing this?
I've tried asking a few of the developers who make these libraries for help but most of them are linux users so they don't really know. An exhaustive google search has really lead me nowhere so I'm asking here.
I was able to find the answer.
The windows cuda installer installs things by default into a weird path:
C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v8.0\include
This path caused a lot of pain for the compiler as a result of the spaces in the folder names. After reinstalling Cuda into C:\CUDA\v8.0 and then appending my CFLAGS and LDFLAGS appropriately in my CGO file I was able to get things to run correctly.
For reference here are the CFLAGS and LDFLAGS that I used to get this to work:
//#cgo windows LDFLAGS:-LC:/cuda/v8.0/lib/x64
//#cgo windows CFLAGS: -IC:/cuda/v8.0/include
import "C"
This was with the github.com/chewxy/cu go library. I also appended the new flags into that library in the cgoflags.go file because the maintainer did not have version 8 or version 9 in there already. I mentioned this to him and he might update it later but for now that's what you have to do.
I'm having a strange problem with include files and an apparent disconnect between Eclipse's build process and its error reporting. I'll give detailed steps to reproducing this problem, so we can narrow the causes down as quickly as possible.
Eclipse 3.7.1 (Indigo SR1) for C/C++ Linux Developers, Ubuntu 10.10 64-bits
It all started when I imported an existing project that "makes" just fine on its own: I thought Eclipse would help considerably in navigating the files and figuring out what does what. However, some of the #included system headers seemed not to be having the correct effect in Eclipse's view. This was very puzzling, and in the course of investigating this, I managed to recreate the problem in a tiny sand box.
Step one: Create a new C project (File: New: C Project) using the Hello World ANSI C Project sample. The parameters are Executable: Hello World ANSI C Project/Linux GCC, the remaining Empty projects set to Linux GCC, and GNU Autotools set to Hello World ANSI C Autotools Project. Call it "hello". Be sure to generate the makefile automatically (Advanced Settings, I believe it is the default).
Step two: Adjust the include path. Using Project: Properties: C/C++ General: Paths and Symbols: Includes: GNU C, set the search path to /usr/local/include, /usr/lib/gcc/x86_64-linux-gnu/4.4.5/include, /usr/include. The second path depends on the exact version of gcc you have installed. This doesn't matter too much, as long as the build path includes at least /usr/include.
Now if you open hello.c, it looks very simple, and Eclipse is quite happy except for return EXIT_SUCCESS;, which cannot resolve EXIT_SUCCESS. Replace EXIT_SUCCESS with a zero (0) and Eclipse gives the all-clear. Select Project: Build Project to generate the executable.
Open a command-line window and drill down to your Eclipse workspace folder's hello/Debug subfolder. Once there, you can run the executable with the line ./hello.
Now the fun begins. Modify hello.c to read in its latter part:
#include <fcntl.h>
int main(void) {
printf("Hello World!\n");
int zz = SPLICE_F_MOVE;
printf("zz (SPLICE_F_MOVE) is '%d'\n", zz);
printf("Bye World!\n");
return 0;
}
You'll get an error on the int zz... line: "Symbol 'SPLICE_F_MOVE' could not be resolved". If you Build the project, you'll get a similar error in the console view: "error: 'SPLICE_F_MOVE' undeclared".
Now if you change the preamble to:
#define _GNU_SOURCE
#include <fcntl.h>
You still get the error on the int zz line (in the editor), but the project will Build correctly! You can confirm this by running the binary in the command-line window you opened earlier. This is really odd since examination of /usr/include/fcntl.h will show that it #includes <bits/fcntl.h>, and that latter header #defines SPLICE_F_MOVE (and a bunch of others) in a block guarded by #ifdef __USE_GNU (__USE_GNU gets #defined if _GNU_SOURCE is #defined). Why on Earth isn't our #define _GNU_SOURCE properly propagated in the workspace perspective?
So this is my problem in a nutshell: why is it the editor (and all of Eclipse CDT) reports an error (apparently by refusing to process correctly an include), but that the underlying build succeeds?
I had similar problems working with GNU and non-GNU compliant toolchains for cross-compiling various microcontrollers. CDT reports lots of errors, but the actual build works perfectly, even when all the header includes are correctly located in the project settings.
The problem is in how CDT operates as distinct from your make system build. CDT is a standalone lexer, parser, and preprocessor and doesn't make use of the toolchain you're using to do the build. This normally would work fine once you set the project settings to match those generated as command-line arguments to your build tools, but many toolchains frequently include hidden implicit defines as part of their compiler/preprocessor itself. The documentation for the implict/hidden defines is usually sketchy and incomplete in my experience, making it nearly impossible to determine which defines are set for a given toolchain (sometimes even dependent on build options) and what they mean. While it may look like you have all the correct defines set to reach the one you're having a problem with, I usually find (especially with GNU) that there are some you're missing that prevent the switch from being processed the way you expected.
When I debug something like this, I first make sure any headers in my project directory are found first if they have names matching those in other directories, then I slowly start moving headers from the standard include folder to my project folder. CDT doesn't do a very good job of indicating which possible versions of a header file it's parsing first, and it frequently pulls system environment settings when you least expect it, but it does look in your project folder for headers first (if you haven't set the system headers path in your project settings to take precedence). By moving the system headers from the location you're looking at to your project directory, you know for sure exactly which header file is being parsed by CDT. Furthermore, if you rebuild your index after doing the move, then open the file in Eclipse, CDT will indicate what switches it believes are enabled or disabled by greying-out or folding the branches not enabled in the header. Following this process has solved this exact problem for me every time, revealing when I had paths to multiple copies of the same header, accidentally duplicated headers, had defines or includes under unexpected switches, etc.
I have the same issue, but didn't even do anything that complicated to produce it--I just made a hello world project of the type you describe and get the same error. Note that, however, in my case, it may be due to a borked install of cygwin--for instance, I had other errors concerning failing to include the .h files, and a complete deletion/reinstall of cygwin removed those errors but the 'Symbol ... Could not be resolved' error remains.
I then decided to make a second such project, and they both report such an error in the 'problems' view, but only one of the projects actually shows the error underlined etc. in the editor (!)
Maybe this issue comes from Ijndigo itself. Did you tried the same with the latest Indigo SR2? I opened a number of bugs for Indigo and its SR1 in eclipse bugzilla.
I've been using VS2008/2010 for a while and I'm going to learn using Eclipse Helions for C/C++ development (mainly C).
I am abit confused about libraries and includes though.
1) How do you properly include winsock2.h for example? I've tried this:
#ifndef CONFIG_H_
#define CONFIG_H_
/* Windows-Build */
#if defined(WIN32) || defined(_WIN32)
#include <winsock2.h>
#endif
SOCKET sock;
#endif /* CONFIG_H_ */
But the compiler dosn't recognise SOCKET. Do you have to manually add the full path to winsock2 somewhere?
2) What about ws2_32.lib? Where do you include that in Eclipse? Do you have to add a path as well?
3) Having used VS mostly I'm new to makefiles. How do you include custom makefiles? Is there a good guide for starting with makefiles?
4) Is there a intellisense like in VS?
That's what I can figure out right now.
Thanks!
EDIT:
In response to the first answer:
Building target: Filesharing_core.dll
Invoking: Cygwin C Linker
gcc -L"C:\cygwin\lib\w32api" -shared -o"Filesharing_core.dll" ./src/test.o -llibws2_32.a
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: cannot find -llibws2_32.a
collect2: ld returned 1 exit status
make: *** [Filesharing_core.dll] Error 1
First off, cygwin will usually use GCC as it's compiler. That means that there's no special windows support that you'll find in the VS compiler and editor. Be prepared to get your hands dirty.
Keep in mind that my CDT version is a bit old and I don't have Cygwin installed so some of the things below might not be accurate. Also all the compiler options that I mention are detailled in the gcc manual.
1) In your sample, nobody is defining WIN32 or _WIN32 (I don't think GCC is going to do that for you but do check). To fix that, you'll have to include the windows.h header which (I think) will take care of definning the correct macros. You could also use the -D compiler switch (configurable in your makefile or through the eclipse menus).
If you encounter missing include errors once you've fixed the defines, I believe that the windows headers are located in the C:\cygwin\usr\include\w32api folder. To add that to your include path, simply open your project properties and navigate to C/C++ General > Paths and Symbols. Add the path to the GNU C group in the Includes tabs. Depending on how you configured your project, this might have already been done for you.
If you're building with your own makefile, you should still do the previous step because it will allow the indexer to find and parse those headers. To tell the compiler about the include folder, use the -I switch.
2) I'm going to guess that ws2_32.lib is the lib file for winsock2. If this is the case, I'm not entirely sure who's responsible for building it (is there a .dll you can use instead?). You might want to check your c:\cygwin\usr\lib folder or the c:\cygwin\usr\local\lib.
If you're using a managed project (eclipse builds the makefile for you) then go to your project properties and navigate to C/C++ Build > Settings. In the Tool Settings tab, go to the libraries item in the linker section. Just add the name of the lib file and the folder in the appropriate boxes.
In your own makefile you'll want to use the -l compiler switch to specify a library and the -L compiler switch to specify a search path.
3) A good place to get started with makefiles would be the GNU make manual.
One detail about running a Makefile on Windows: make sure to use the shell provided by Cygwin or MinGW. Otherwise, commands like rm won't be defined and it'll make your life very difficult.
You might also want to consider CMake. It's easier to use and scales better to larger projects.
To use a hand-made makefile in your project, just create an new Makefile project and dump your Makefile file in the root of your project folder. That's it.
4) Yes there is but it's not called intellisense. Just hit CTRL+Space anywhere in your source code to bring it up.
Other fun tools can be found in the right-click menu. My personal favorites include CTRL+SHIFT+R to find and open a file, CTRL+SHIFT+T to find and open a type\variable\function\define and CTRL+O to find and goto a type\variable\function\define within the opened file.
The indexer can go a little crazy sometimes (mostly when parsing C++ code). You can modify its behaviour by going in the Windows > Preferences menu at the top and navigating to the C/C++ > Indexer item.
I hope this helps.