VisualC.html
author Sam Lantinga <slouken@libsdl.org>
Thu, 13 Oct 2016 04:54:43 -0700
changeset 10530 2a3f8bc23daa
parent 10052 541e2b6818a7
permissions -rw-r--r--
Fixed bug 3328 - Race condition in Wayland_VideoInit

Robert Folland

When running this little test program with SDL2 on Wayland it often crashes in SDL_Init.

From a backtrace it is apparent that there is a race condition in creating a xkb_context_ref. Sometimes it is 0x0.

By moving the relevant lines higher up in Wayland_VideoInit (in SDL2-2.0.4/src/video/wayland/SDL_waylandvideo.c:302) this seems to get fixed.

I moved the call to WAYLAND_xkb_context_new() up to before the call to WAYLAND_wl_display_connect().

Here is the test program (just a loop of init and quit), and a backtrace from gdb:

#include <cstdio>
#include <stdlib.h>
#include <SDL2/SDL.h>
#include <unistd.h>
#include <iostream>

int main(int argc, char **argv)
{
int count = atoi(argv[1]);

for (int i = 0; i < count; i++) {
std::cout << "Init " << i << std::endl;
if (SDL_Init(SDL_INIT_VIDEO) < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
"Couldn't initialize SDL: %s\n",
SDL_GetError());
return 1;
}
std::cout << "Quit" << std::endl;
SDL_Quit();
}
return 0;
}


Init 12
Quit
Init 13

Program received signal SIGSEGV, Segmentation fault.
xkb_context_ref (ctx=ctx@entry=0x0) at src/context.c:156
156 ctx->refcnt++;
(gdb) bt
#0 xkb_context_ref (ctx=ctx@entry=0x0) at src/context.c:156
#1 0x00007ffff5e1cd4c in xkb_keymap_new (ctx=0x0, format=XKB_KEYMAP_FORMAT_TEXT_V1, flags=flags@entry=XKB_KEYMAP_COMPILE_NO_FLAGS) at src/keymap-priv.c:65
#2 0x00007ffff5e1c6cc in xkb_keymap_new_from_buffer (ctx=<optimized out>,
buffer=0x7ffff7fd5000 "xkb_keymap {\nxkb_keycodes \"(unnamed)\" {\n\tminimum = 8;\n\tmaximum = 255;\n\t<ESC>", ' ' <repeats 16 times>, "= 9;\n\t<AE01>", ' ' <re
peats 15 times>, "= 10;\n\t<AE02>", ' ' <repeats 15 times>, "= 11;\n\t<AE03>", ' ' <repeats 15 times>, "= 12;\n\t<AE04>", ' ' <repeats 12 times>..., length=48090,
format=<optimized out>, flags=<optimized out>) at src/keymap.c:191
#3 0x00007ffff7b8ea4e in keyboard_handle_keymap (data=0x6169b0, keyboard=<optimized out>, format=<optimized out>, fd=5, size=48091)
at /home/vlab/abs/sdl2/src/SDL2-2.0.4/src/video/wayland/SDL_waylandevents.c:269
#4 0x00007ffff64501f0 in ffi_call_unix64 () from /usr/lib/libffi.so.6
#5 0x00007ffff644fc58 in ffi_call () from /usr/lib/libffi.so.6
#6 0x00007ffff665be3e in wl_closure_invoke (closure=closure@entry=0x61f000, flags=flags@entry=1, target=<optimized out>, target@entry=0x616d20,
opcode=opcode@entry=0, data=<optimized out>) at src/connection.c:949
#7 0x00007ffff6658be0 in dispatch_event (display=<optimized out>, queue=<optimized out>) at src/wayland-client.c:1274
#8 0x00007ffff6659db4 in dispatch_queue (queue=0x617398, display=0x6172d0) at src/wayland-client.c:1420
#9 wl_display_dispatch_queue_pending (display=0x6172d0, queue=0x617398) at src/wayland-client.c:1662
#10 0x00007ffff665a0cf in wl_display_roundtrip_queue (display=0x6172d0, queue=0x617398) at src/wayland-client.c:1085
#11 0x00007ffff7b8faa0 in Wayland_VideoInit (_this=<optimized out>) at /home/vlab/abs/sdl2/src/SDL2-2.0.4/src/video/wayland/SDL_waylandvideo.c:302
#12 0x00007ffff7b7aed6 in SDL_VideoInit_REAL (driver_name=<optimized out>, driver_name@entry=0x0) at /home/vlab/abs/sdl2/src/SDL2-2.0.4/src/video/SDL_video.c:513
#13 0x00007ffff7ae0ee7 in SDL_InitSubSystem_REAL (flags=16416) at /home/vlab/abs/sdl2/src/SDL2-2.0.4/src/SDL.c:173
#14 0x0000000000400b24 in main (argc=2, argv=0x7fffffffebb8) at vplay-init.cpp:13
(gdb)
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<HTML>
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	<HEAD>
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		<TITLE>Using SDL with Microsoft Visual C++</TITLE>
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	</HEAD>
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	<BODY>
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		<H1>
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			Using SDL with Microsoft Visual C++
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		</H1>
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		<H3>
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			by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro </A>and additions by <A HREF="mailto:james@conceptofzero.net">
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				James Turk</A>
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		</H3>
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		<p>
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			You can either use the precompiled libraries from <A HREF="http://www.libsdl.org/download.php"> the SDL Download web site </A>, or you can build SDL yourself.
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		</p>
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		<H3>
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			Building SDL
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		</H3>
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		<P>
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			Go into the VisualC directory and double-click on the Visual Studio solution for your version of Visual Studio, e.g. <CODE>SDL_VS2008.sln</CODE> This should open up the IDE.
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		</P>
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		<P>
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			There are different solution files for the various
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			versions of the IDE. Please use the appropriate version
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			2008, 2010, 2012 or 2013.
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		</P>
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		<P>
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			Build the <CODE>.dll</CODE> and <CODE>.lib</CODE> files.
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		</P>
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		<P>
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			This is done by right clicking on each project in turn (Projects are listed in 
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			the Workspace panel in the FileView tab), and selecting "Build".
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		</P>
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		<P>
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			You may get a few warnings, but you should not get any errors. You do have to 
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			have at least the DirectX 9 SDK installed, however. The latest 
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			version of DirectX can be downloaded from <A HREF="http://www.microsoft.com">Microsoft</A>.
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		</P>
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		<P>
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			Later, we will refer to the following .lib and .dll files that have just been 
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			generated:
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		</P>
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		<ul>
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    <li> SDL2.dll</li>
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    <li> SDL2.lib</li>
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    <li> SDL2main.lib</li>
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    </ul>
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		<P>
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			Search for these using the Windows Find (Windows-F) utility inside the VisualC directory.
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		</P>
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		<H3>
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			Creating a Project with SDL
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		</H3>
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		<P>
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			Create a project as a Win32 Application.
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		</P>
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		<P>
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			Create a C++ file for your project.
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		</P>
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		<P>
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			Set the C runtime to "Multi-threaded DLL" in the menu: <CODE>Project|Settings|C/C++ 
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				tab|Code Generation|Runtime Library </CODE>.
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		</P>
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		<P>
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			Add the SDL <CODE>include</CODE> directory to your list of includes in the 
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			menu: <CODE>Project|Settings|C/C++ tab|Preprocessor|Additional include directories </CODE>
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			.
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			<br>
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			<STRONG><FONT color="#009900">VC7 Specific: Instead of doing this I find it easier to 
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					add the include and library directories to the list that VC7 keeps. Do this by 
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					selecting Tools|Options|Projects|VC++ Directories and under the "Show 
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					Directories For:" dropbox select "Include Files", and click the "New Directory 
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					Icon" and add the [SDLROOT]\include directory (e.g. If you installed to 
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					c:\SDL\ add c:\SDL\include).&nbsp;Proceed to&nbsp;change the 
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					dropbox selection to "Library Files" and add [SDLROOT]\lib.</FONT></STRONG>
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		</P>
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			<P>
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				The "include directory" I am referring to is the <CODE>include</CODE> folder 
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				within the main SDL directory (the one that this HTML file located within).
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			</P>
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			<P>
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				Now we're going to use the files that we had created earlier in the Build SDL 
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				step.
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			</P>
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			<P>
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				Copy the following files into your Project directory:
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			</P>
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			<ul>
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     <li> SDL2.dll</li>
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     </ul>
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			<P>
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				Add the following files to your project (It is not necessary to copy them to 
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				your project directory):
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			</P>
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			<ul>
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     <li> SDL2.lib </li>
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     <li> SDL2main.lib</li>
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     </ul>
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			<P>
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				(To add them to your project, right click on your project, and select "Add 
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				files to project")
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			</P>
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		<P><STRONG><FONT color="#009900">Instead of adding the files to your project it is more 
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					desirable to add them to the linker options: Project|Properties|Linker|Command 
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					Line and type the names of the libraries to link with in the "Additional 
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					Options:" box.&nbsp; Note: This must be done&nbsp;for&nbsp;each&nbsp;build 
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					configuration (e.g. Release,Debug).</FONT></STRONG></P>
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		<H3>
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			SDL 101, First Day of Class
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		</H3>
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		<P>
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			Now create the basic body of your project. The body of your program should take 
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			the following form:
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			<PRE><CODE>
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#include "SDL.h"
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int main( int argc, char* argv[] )
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{
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  // Body of the program goes here.
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  return 0;
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}
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			</CODE></PRE>
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		<P></P>
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		<H3>
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			That's it!
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		</H3>
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		<P>
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			I hope that this document has helped you get through the most difficult part of 
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			using the SDL: installing it. Suggestions for improvements to this document 
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			should be sent to the writers of this document.
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		</P>
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		<P>
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			Thanks to Paulus Esterhazy (pesterhazy@gmx.net), for the work on VC++ port.
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		</P>
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		<P>
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			This document was originally called "VisualC.txt", and was written by <A HREF="mailto:slouken@libsdl.org">
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				Sam Lantinga</A>.
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		</P>
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		<P>
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			Later, it was converted to HTML and expanded into the document that you see 
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			today by <A HREF="mailto:snowlion@sprynet.com">Lion Kimbro</A>.
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		</P>
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		<P>Minor Fixes and Visual C++ 7 Information (In Green) was added by <A HREF="mailto:james@conceptofzero.net">James Turk</A>
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		</P>
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	</BODY>
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</HTML>