Mercurial > sdl-ios-xcode
view docs/html/index.html @ 4139:568c9b3c0167 SDL-1.2
* Added configure option --enable-screensaver, to allow enabling the screensaver by default.
* Use XResetScreenSaver() instead of disabling screensaver entirely.
Full discussion summary from Erik on the SDL mailing list:
Current behaviour
=================
SDL changes the user's display power management settings without
permission from the user and without telling the user.
The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).
In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).
The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.
The problems that the current behaviour tries to solve
======================================================
1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".
2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.
3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.
How the problems should be solved
=================================
The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).
1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.
2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.
3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 29 Feb 2008 13:55:44 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE ></TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="NEXT" TITLE="SDL Guide" HREF="guide.html"></HEAD ><BODY CLASS="BOOK" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="BOOK" ><A NAME="AEN1" ></A ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >I. <A HREF="guide.html" >SDL Guide</A ></DT ><DD ><DL ><DT ><A HREF="guidepreface.html" >Preface</A ></DT ><DD ><DL ><DT ><A HREF="guidepreface.html#GUIDEABOUTSDL" >About SDL</A ></DT ><DT ><A HREF="guideaboutsdldoc.html" >About SDLdoc</A ></DT ><DT ><A HREF="guidecredits.html" >Credits</A ></DT ></DL ></DD ><DT >1. <A HREF="guidethebasics.html" >The Basics</A ></DT ><DD ><DL ><DT ><A HREF="guidethebasics.html#GUIDEINTRODUCTION" >Introduction</A ></DT ><DT ><A HREF="guidebasicsinit.html" >Initializing SDL</A ></DT ></DL ></DD ><DT >2. <A HREF="guidevideo.html" >Graphics and Video</A ></DT ><DD ><DL ><DT ><A HREF="guidevideo.html#GUIDEVIDEOINTRO" >Introduction to SDL Video</A ></DT ><DT ><A HREF="guidevideoopengl.html" >Using OpenGL With SDL</A ></DT ></DL ></DD ><DT >3. <A HREF="guideinput.html" >Input handling</A ></DT ><DD ><DL ><DT ><A HREF="guideinput.html#GUIDEINPUTJOYSTICK" >Handling Joysticks</A ></DT ><DT ><A HREF="guideinputkeyboard.html" >Handling the Keyboard</A ></DT ></DL ></DD ><DT >4. <A HREF="guideexamples.html" >Examples</A ></DT ><DD ><DL ><DT ><A HREF="guideexamples.html#AEN369" >Introduction</A ></DT ><DT ><A HREF="guideeventexamples.html" >Event Examples</A ></DT ><DT ><A HREF="guideaudioexamples.html" >Audio Examples</A ></DT ><DT ><A HREF="guidecdromexamples.html" >CDROM Examples</A ></DT ><DT ><A HREF="guidetimeexamples.html" >Time Examples</A ></DT ></DL ></DD ></DL ></DD ><DT >II. <A HREF="reference.html" >SDL Reference</A ></DT ><DD ><DL ><DT >5. <A HREF="general.html" >General</A ></DT ><DD ><DL ><DT ><A HREF="sdlinit.html" >SDL_Init</A > -- Initializes SDL</DT ><DT ><A HREF="sdlinitsubsystem.html" >SDL_InitSubSystem</A > -- Initialize subsystems</DT ><DT ><A HREF="sdlquitsubsystem.html" >SDL_QuitSubSystem</A > -- Shut down a subsystem</DT ><DT ><A HREF="sdlquit.html" >SDL_Quit</A > -- Shut down SDL</DT ><DT ><A HREF="sdlwasinit.html" >SDL_WasInit</A > -- Check which subsystems are initialized</DT ><DT ><A HREF="sdlgeterror.html" >SDL_GetError</A > -- Get SDL error string</DT ><DT ><A HREF="sdlenvvars.html" >SDL_envvars</A > -- SDL environment variables</DT ></DL ></DD ><DT >6. <A HREF="video.html" >Video</A ></DT ><DD ><DL ><DT ><A HREF="sdlgetvideosurface.html" >SDL_GetVideoSurface</A > -- returns a pointer to the current display surface</DT ><DT ><A HREF="sdlgetvideoinfo.html" >SDL_GetVideoInfo</A > -- returns a pointer to information about the video hardware</DT ><DT ><A HREF="sdlvideodrivername.html" >SDL_VideoDriverName</A > -- Obtain the name of the video driver</DT ><DT ><A HREF="sdllistmodes.html" >SDL_ListModes</A > -- Returns a pointer to an array of available screen dimensions for the given format and video flags</DT ><DT ><A HREF="sdlvideomodeok.html" >SDL_VideoModeOK</A > -- Check to see if a particular video mode is supported.</DT ><DT ><A HREF="sdlsetvideomode.html" >SDL_SetVideoMode</A > -- Set up a video mode with the specified width, height and bits-per-pixel.</DT ><DT ><A HREF="sdlupdaterect.html" >SDL_UpdateRect</A > -- Makes sure the given area is updated on the given screen.</DT ><DT ><A HREF="sdlupdaterects.html" >SDL_UpdateRects</A > -- Makes sure the given list of rectangles is updated on the given screen.</DT ><DT ><A HREF="sdlflip.html" >SDL_Flip</A > -- Swaps screen buffers</DT ><DT ><A HREF="sdlsetcolors.html" >SDL_SetColors</A > -- Sets a portion of the colormap for the given 8-bit surface.</DT ><DT ><A HREF="sdlsetpalette.html" >SDL_SetPalette</A > -- Sets the colors in the palette of an 8-bit surface.</DT ><DT ><A HREF="sdlsetgamma.html" >SDL_SetGamma</A > -- Sets the color gamma function for the display</DT ><DT ><A HREF="sdlgetgammaramp.html" >SDL_GetGammaRamp</A > -- Gets the color gamma lookup tables for the display</DT ><DT ><A HREF="sdlsetgammaramp.html" >SDL_SetGammaRamp</A > -- Sets the color gamma lookup tables for the display</DT ><DT ><A HREF="sdlmaprgb.html" >SDL_MapRGB</A > -- Map a RGB color value to a pixel format.</DT ><DT ><A HREF="sdlmaprgba.html" >SDL_MapRGBA</A > -- Map a RGBA color value to a pixel format.</DT ><DT ><A HREF="sdlgetrgb.html" >SDL_GetRGB</A > -- Get RGB values from a pixel in the specified pixel format.</DT ><DT ><A HREF="sdlgetrgba.html" >SDL_GetRGBA</A > -- Get RGBA values from a pixel in the specified pixel format.</DT ><DT ><A HREF="sdlcreatergbsurface.html" >SDL_CreateRGBSurface</A > -- Create an empty SDL_Surface</DT ><DT ><A HREF="sdlcreatergbsurfacefrom.html" >SDL_CreateRGBSurfaceFrom</A > -- Create an SDL_Surface from pixel data</DT ><DT ><A HREF="sdlfreesurface.html" >SDL_FreeSurface</A > -- Frees (deletes) a SDL_Surface</DT ><DT ><A HREF="sdllocksurface.html" >SDL_LockSurface</A > -- Lock a surface for directly access.</DT ><DT ><A HREF="sdlunlocksurface.html" >SDL_UnlockSurface</A > -- Unlocks a previously locked surface.</DT ><DT ><A HREF="sdlloadbmp.html" >SDL_LoadBMP</A > -- Load a Windows BMP file into an SDL_Surface.</DT ><DT ><A HREF="sdlsavebmp.html" >SDL_SaveBMP</A > -- Save an SDL_Surface as a Windows BMP file.</DT ><DT ><A HREF="sdlsetcolorkey.html" >SDL_SetColorKey</A > -- Sets the color key (transparent pixel) in a blittable surface and RLE acceleration.</DT ><DT ><A HREF="sdlsetalpha.html" >SDL_SetAlpha</A > -- Adjust the alpha properties of a surface</DT ><DT ><A HREF="sdlsetcliprect.html" >SDL_SetClipRect</A > -- Sets the clipping rectangle for a surface.</DT ><DT ><A HREF="sdlgetcliprect.html" >SDL_GetClipRect</A > -- Gets the clipping rectangle for a surface.</DT ><DT ><A HREF="sdlconvertsurface.html" >SDL_ConvertSurface</A > -- Converts a surface to the same format as another surface.</DT ><DT ><A HREF="sdlblitsurface.html" >SDL_BlitSurface</A > -- This performs a fast blit from the source surface to the destination surface.</DT ><DT ><A HREF="sdlfillrect.html" >SDL_FillRect</A > -- This function performs a fast fill of the given rectangle with some color</DT ><DT ><A HREF="sdldisplayformat.html" >SDL_DisplayFormat</A > -- Convert a surface to the display format</DT ><DT ><A HREF="sdldisplayformatalpha.html" >SDL_DisplayFormatAlpha</A > -- Convert a surface to the display format</DT ><DT ><A HREF="sdlwarpmouse.html" >SDL_WarpMouse</A > -- Set the position of the mouse cursor.</DT ><DT ><A HREF="sdlcreatecursor.html" >SDL_CreateCursor</A > -- Creates a new mouse cursor.</DT ><DT ><A HREF="sdlfreecursor.html" >SDL_FreeCursor</A > -- Frees a cursor created with SDL_CreateCursor.</DT ><DT ><A HREF="sdlsetcursor.html" >SDL_SetCursor</A > -- Set the currently active mouse cursor.</DT ><DT ><A HREF="sdlgetcursor.html" >SDL_GetCursor</A > -- Get the currently active mouse cursor.</DT ><DT ><A HREF="sdlshowcursor.html" >SDL_ShowCursor</A > -- Toggle whether or not the cursor is shown on the screen.</DT ><DT ><A HREF="sdlglloadlibrary.html" >SDL_GL_LoadLibrary</A > -- Specify an OpenGL library</DT ><DT ><A HREF="sdlglgetprocaddress.html" >SDL_GL_GetProcAddress</A > -- Get the address of a GL function</DT ><DT ><A HREF="sdlglgetattribute.html" >SDL_GL_GetAttribute</A > -- Get the value of a special SDL/OpenGL attribute</DT ><DT ><A HREF="sdlglsetattribute.html" >SDL_GL_SetAttribute</A > -- Set a special SDL/OpenGL attribute</DT ><DT ><A HREF="sdlglswapbuffers.html" >SDL_GL_SwapBuffers</A > -- Swap OpenGL framebuffers/Update Display</DT ><DT ><A HREF="sdlcreateyuvoverlay.html" >SDL_CreateYUVOverlay</A > -- Create a YUV video overlay</DT ><DT ><A HREF="sdllockyuvoverlay.html" >SDL_LockYUVOverlay</A > -- Lock an overlay</DT ><DT ><A HREF="sdlunlockyuvoverlay.html" >SDL_UnlockYUVOverlay</A > -- Unlock an overlay</DT ><DT ><A HREF="sdldisplayyuvoverlay.html" >SDL_DisplayYUVOverlay</A > -- Blit the overlay to the display</DT ><DT ><A HREF="sdlfreeyuvoverlay.html" >SDL_FreeYUVOverlay</A > -- Free a YUV video overlay</DT ><DT ><A HREF="sdlglattr.html" >SDL_GLattr</A > -- SDL GL Attributes</DT ><DT ><A HREF="sdlrect.html" >SDL_Rect</A > -- Defines a rectangular area</DT ><DT ><A HREF="sdlcolor.html" >SDL_Color</A > -- Format independent color description</DT ><DT ><A HREF="sdlpalette.html" >SDL_Palette</A > -- Color palette for 8-bit pixel formats</DT ><DT ><A HREF="sdlpixelformat.html" >SDL_PixelFormat</A > -- Stores surface format information</DT ><DT ><A HREF="sdlsurface.html" >SDL_Surface</A > -- Graphical Surface Structure</DT ><DT ><A HREF="sdlvideoinfo.html" >SDL_VideoInfo</A > -- Video Target information</DT ><DT ><A HREF="sdloverlay.html" >SDL_Overlay</A > -- YUV video overlay</DT ></DL ></DD ><DT >7. <A HREF="wm.html" >Window Management</A ></DT ><DD ><DL ><DT ><A HREF="sdlwmsetcaption.html" >SDL_WM_SetCaption</A > -- Sets the window tile and icon name.</DT ><DT ><A HREF="sdlwmgetcaption.html" >SDL_WM_GetCaption</A > -- Gets the window title and icon name.</DT ><DT ><A HREF="sdlwmseticon.html" >SDL_WM_SetIcon</A > -- Sets the icon for the display window.</DT ><DT ><A HREF="sdlwmiconifywindow.html" >SDL_WM_IconifyWindow</A > -- Iconify/Minimise the window</DT ><DT ><A HREF="sdlwmtogglefullscreen.html" >SDL_WM_ToggleFullScreen</A > -- Toggles fullscreen mode</DT ><DT ><A HREF="sdlwmgrabinput.html" >SDL_WM_GrabInput</A > -- Grabs mouse and keyboard input.</DT ></DL ></DD ><DT >8. <A HREF="event.html" >Events</A ></DT ><DD ><DL ><DT ><A HREF="event.html#AEN3691" >Introduction</A ></DT ><DT ><A HREF="eventstructures.html" >SDL Event Structures.</A ></DT ><DT ><A HREF="eventfunctions.html" >Event Functions.</A ></DT ></DL ></DD ><DT >9. <A HREF="joystick.html" >Joystick</A ></DT ><DD ><DL ><DT ><A HREF="sdlnumjoysticks.html" >SDL_NumJoysticks</A > -- Count available joysticks.</DT ><DT ><A HREF="sdljoystickname.html" >SDL_JoystickName</A > -- Get joystick name.</DT ><DT ><A HREF="sdljoystickopen.html" >SDL_JoystickOpen</A > -- Opens a joystick for use.</DT ><DT ><A HREF="sdljoystickopened.html" >SDL_JoystickOpened</A > -- Determine if a joystick has been opened</DT ><DT ><A HREF="sdljoystickindex.html" >SDL_JoystickIndex</A > -- Get the index of an SDL_Joystick.</DT ><DT ><A HREF="sdljoysticknumaxes.html" >SDL_JoystickNumAxes</A > -- Get the number of joystick axes</DT ><DT ><A HREF="sdljoysticknumballs.html" >SDL_JoystickNumBalls</A > -- Get the number of joystick trackballs</DT ><DT ><A HREF="sdljoysticknumhats.html" >SDL_JoystickNumHats</A > -- Get the number of joystick hats</DT ><DT ><A HREF="sdljoysticknumbuttons.html" >SDL_JoystickNumButtons</A > -- Get the number of joysitck buttons</DT ><DT ><A HREF="sdljoystickupdate.html" >SDL_JoystickUpdate</A > -- Updates the state of all joysticks</DT ><DT ><A HREF="sdljoystickgetaxis.html" >SDL_JoystickGetAxis</A > -- Get the current state of an axis</DT ><DT ><A HREF="sdljoystickgethat.html" >SDL_JoystickGetHat</A > -- Get the current state of a joystick hat</DT ><DT ><A HREF="sdljoystickgetbutton.html" >SDL_JoystickGetButton</A > -- Get the current state of a given button on a given joystick</DT ><DT ><A HREF="sdljoystickgetball.html" >SDL_JoystickGetBall</A > -- Get relative trackball motion</DT ><DT ><A HREF="sdljoystickclose.html" >SDL_JoystickClose</A > -- Closes a previously opened joystick</DT ></DL ></DD ><DT >10. <A HREF="audio.html" >Audio</A ></DT ><DD ><DL ><DT ><A HREF="sdlaudiospec.html" >SDL_AudioSpec</A > -- Audio Specification Structure</DT ><DT ><A HREF="sdlopenaudio.html" >SDL_OpenAudio</A > -- Opens the audio device with the desired parameters.</DT ><DT ><A HREF="sdlpauseaudio.html" >SDL_PauseAudio</A > -- Pauses and unpauses the audio callback processing</DT ><DT ><A HREF="sdlgetaudiostatus.html" >SDL_GetAudioStatus</A > -- Get the current audio state</DT ><DT ><A HREF="sdlloadwav.html" >SDL_LoadWAV</A > -- Load a WAVE file</DT ><DT ><A HREF="sdlfreewav.html" >SDL_FreeWAV</A > -- Frees previously opened WAV data</DT ><DT ><A HREF="sdlaudiocvt.html" >SDL_AudioCVT</A > -- Audio Conversion Structure</DT ><DT ><A HREF="sdlbuildaudiocvt.html" >SDL_BuildAudioCVT</A > -- Initializes a SDL_AudioCVT structure for conversion</DT ><DT ><A HREF="sdlconvertaudio.html" >SDL_ConvertAudio</A > -- Convert audio data to a desired audio format.</DT ><DT ><A HREF="sdlmixaudio.html" >SDL_MixAudio</A > -- Mix audio data</DT ><DT ><A HREF="sdllockaudio.html" >SDL_LockAudio</A > -- Lock out the callback function</DT ><DT ><A HREF="sdlunlockaudio.html" >SDL_UnlockAudio</A > -- Unlock the callback function</DT ><DT ><A HREF="sdlcloseaudio.html" >SDL_CloseAudio</A > -- Shuts down audio processing and closes the audio device.</DT ></DL ></DD ><DT >11. <A HREF="cdrom.html" >CD-ROM</A ></DT ><DD ><DL ><DT ><A HREF="sdlcdnumdrives.html" >SDL_CDNumDrives</A > -- Returns the number of CD-ROM drives on the system.</DT ><DT ><A HREF="sdlcdname.html" >SDL_CDName</A > -- Returns a human-readable, system-dependent identifier for the CD-ROM.</DT ><DT ><A HREF="sdlcdopen.html" >SDL_CDOpen</A > -- Opens a CD-ROM drive for access.</DT ><DT ><A HREF="sdlcdstatus.html" >SDL_CDStatus</A > -- Returns the current status of the given drive.</DT ><DT ><A HREF="sdlcdplay.html" >SDL_CDPlay</A > -- Play a CD</DT ><DT ><A HREF="sdlcdplaytracks.html" >SDL_CDPlayTracks</A > -- Play the given CD track(s)</DT ><DT ><A HREF="sdlcdpause.html" >SDL_CDPause</A > -- Pauses a CDROM</DT ><DT ><A HREF="sdlcdresume.html" >SDL_CDResume</A > -- Resumes a CDROM</DT ><DT ><A HREF="sdlcdstop.html" >SDL_CDStop</A > -- Stops a CDROM</DT ><DT ><A HREF="sdlcdeject.html" >SDL_CDEject</A > -- Ejects a CDROM</DT ><DT ><A HREF="sdlcdclose.html" >SDL_CDClose</A > -- Closes a SDL_CD handle</DT ><DT ><A HREF="sdlcd.html" >SDL_CD</A > -- CDROM Drive Information</DT ><DT ><A HREF="sdlcdtrack.html" >SDL_CDtrack</A > -- CD Track Information Structure</DT ></DL ></DD ><DT >12. <A HREF="thread.html" >Multi-threaded Programming</A ></DT ><DD ><DL ><DT ><A HREF="sdlcreatethread.html" >SDL_CreateThread</A > -- Creates a new thread of execution that shares its parent's properties.</DT ><DT ><A HREF="sdlthreadid.html" >SDL_ThreadID</A > -- Get the 32-bit thread identifier for the current thread.</DT ><DT ><A HREF="sdlgetthreadid.html" >SDL_GetThreadID</A > -- Get the SDL thread ID of a SDL_Thread</DT ><DT ><A HREF="sdlwaitthread.html" >SDL_WaitThread</A > -- Wait for a thread to finish.</DT ><DT ><A HREF="sdlkillthread.html" >SDL_KillThread</A > -- Gracelessly terminates the thread.</DT ><DT ><A HREF="sdlcreatemutex.html" >SDL_CreateMutex</A > -- Create a mutex</DT ><DT ><A HREF="sdldestroymutex.html" >SDL_DestroyMutex</A > -- Destroy a mutex</DT ><DT ><A HREF="sdlmutexp.html" >SDL_mutexP</A > -- Lock a mutex</DT ><DT ><A HREF="sdlmutexv.html" >SDL_mutexV</A > -- Unlock a mutex</DT ><DT ><A HREF="sdlcreatesemaphore.html" >SDL_CreateSemaphore</A > -- Creates a new semaphore and assigns an initial value to it.</DT ><DT ><A HREF="sdldestroysemaphore.html" >SDL_DestroySemaphore</A > -- Destroys a semaphore that was created by <A HREF="sdlcreatesemaphore.html" >SDL_CreateSemaphore</A >.</DT ><DT ><A HREF="sdlsemwait.html" >SDL_SemWait</A > -- Lock a semaphore and suspend the thread if the semaphore value is zero.</DT ><DT ><A HREF="sdlsemtrywait.html" >SDL_SemTryWait</A > -- Attempt to lock a semaphore but don't suspend the thread.</DT ><DT ><A HREF="sdlsemwaittimeout.html" >SDL_SemWaitTimeout</A > -- Lock a semaphore, but only wait up to a specified maximum time.</DT ><DT ><A HREF="sdlsempost.html" >SDL_SemPost</A > -- Unlock a semaphore.</DT ><DT ><A HREF="sdlsemvalue.html" >SDL_SemValue</A > -- Return the current value of a semaphore.</DT ><DT ><A HREF="sdlcreatecond.html" >SDL_CreateCond</A > -- Create a condition variable</DT ><DT ><A HREF="sdldestroycond.html" >SDL_DestroyCond</A > -- Destroy a condition variable</DT ><DT ><A HREF="sdlcondsignal.html" >SDL_CondSignal</A > -- Restart a thread wait on a condition variable</DT ><DT ><A HREF="sdlcondbroadcast.html" >SDL_CondBroadcast</A > -- Restart all threads waiting on a condition variable</DT ><DT ><A HREF="sdlcondwait.html" >SDL_CondWait</A > -- Wait on a condition variable</DT ><DT ><A HREF="sdlcondwaittimeout.html" >SDL_CondWaitTimeout</A > -- Wait on a condition variable, with timeout</DT ></DL ></DD ><DT >13. <A HREF="time.html" >Time</A ></DT ><DD ><DL ><DT ><A HREF="sdlgetticks.html" >SDL_GetTicks</A > -- Get the number of milliseconds since the SDL library initialization.</DT ><DT ><A HREF="sdldelay.html" >SDL_Delay</A > -- Wait a specified number of milliseconds before returning.</DT ><DT ><A HREF="sdladdtimer.html" >SDL_AddTimer</A > -- Add a timer which will call a callback after the specified number of milliseconds has elapsed.</DT ><DT ><A HREF="sdlremovetimer.html" >SDL_RemoveTimer</A > -- Remove a timer which was added with <A HREF="sdladdtimer.html" >SDL_AddTimer</A >.</DT ><DT ><A HREF="sdlsettimer.html" >SDL_SetTimer</A > -- Set a callback to run after the specified number of milliseconds has elapsed.</DT ></DL ></DD ></DL ></DD ></DL ></DIV ><DIV CLASS="LOT" ><DL CLASS="LOT" ><DT ><B >List of Tables</B ></DT ><DT >8-1. <A HREF="sdlkey.html#AEN4720" >SDL Keysym definitions</A ></DT ><DT >8-2. <A HREF="sdlkey.html#SDLMOD" >SDL modifier definitions</A ></DT ></DL ></DIV ><DIV CLASS="LOT" ><DL CLASS="LOT" ><DT ><B >List of Examples</B ></DT ><DT >1-1. <A HREF="guidebasicsinit.html#AEN60" >Initializing SDL</A ></DT ><DT >2-1. <A HREF="guidevideo.html#AEN71" >Initializing the Video Display</A ></DT ><DT >2-2. <A HREF="guidevideo.html#AEN77" >Initializing the Best Video Mode</A ></DT ><DT >2-3. <A HREF="guidevideo.html#AEN83" >Loading and Displaying a BMP File</A ></DT ><DT >2-4. <A HREF="guidevideo.html#AEN90" >getpixel()</A ></DT ><DT >2-5. <A HREF="guidevideo.html#AEN93" >putpixel()</A ></DT ><DT >2-6. <A HREF="guidevideo.html#AEN97" >Using putpixel()</A ></DT ><DT >2-7. <A HREF="guidevideoopengl.html#AEN114" >Initializing SDL with OpenGL</A ></DT ><DT >2-8. <A HREF="guidevideoopengl.html#AEN128" >SDL and OpenGL</A ></DT ><DT >3-1. <A HREF="guideinput.html#AEN141" >Initializing SDL with Joystick Support</A ></DT ><DT >3-2. <A HREF="guideinput.html#AEN154" >Querying the Number of Available Joysticks</A ></DT ><DT >3-3. <A HREF="guideinput.html#AEN183" >Opening a Joystick</A ></DT ><DT >3-4. <A HREF="guideinput.html#AEN191" >Joystick Axis Events</A ></DT ><DT >3-5. <A HREF="guideinput.html#AEN195" >More Joystick Axis Events</A ></DT ><DT >3-6. <A HREF="guideinput.html#AEN203" >Joystick Button Events</A ></DT ><DT >3-7. <A HREF="guideinput.html#AEN217" >Joystick Ball Events</A ></DT ><DT >3-8. <A HREF="guideinput.html#AEN244" >Joystick Hat Events</A ></DT ><DT >3-9. <A HREF="guideinput.html#AEN265" >Querying Joystick Characteristics</A ></DT ><DT >3-10. <A HREF="guideinputkeyboard.html#AEN334" >Reading Keyboard Events</A ></DT ><DT >3-11. <A HREF="guideinputkeyboard.html#AEN351" >Interpreting Key Event Information</A ></DT ><DT >3-12. <A HREF="guideinputkeyboard.html#AEN363" >Proper Game Movement</A ></DT ></DL ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" > </TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="guide.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" > </TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL Guide</TD ></TR ></TABLE ></DIV ></BODY ></HTML >