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view docs/html/sdladdtimer.html @ 3162:dc1eb82ffdaa
Von: Thomas Zimmermann
Betreff: [SDL] [PATCH] Make static variables const
Datum: Tue, 19 May 2009 19:45:37 +0200
Hi,
this is a set of simple changes which make some of SDL's internal static
arrays constant. The purpose is to shrink the number of write-able
static bytes and thus increase the number of memory pages shared between
SDL applications.
The patch set is against trunk@4513. Each of the attached patch files is
specific to a sub-system. The set is completed by a second mail, because
of the list's 40 KiB limit.
The files readelf-r4513.txt and readelf-const-patch.txt where made by
calling 'readelf -S libSDL.so'. They show the difference in ELF sections
without and with the patch. Some numbers measured on my x86-64:
Before
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000008170 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 00000000003045e0 001045e0
00000000000023d0 0000000000000000 WA 0 0 32
[23] .data PROGBITS 00000000003076e0 001076e0
0000000000004988 0000000000000000 WA 0 0 32
After
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000009a50 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 0000000000306040 00106040
0000000000002608 0000000000000000 WA 0 0 32
[23] .data PROGBITS 0000000000309360 00109360
0000000000002e88 0000000000000000 WA 0 0 32
The size of the write-able data section decreased considerably. Some
entries became const-after-relocation, while most of its content went
straight into the read-only data section.
Best regards, Thomas
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 03 Jun 2009 04:37:27 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_AddTimer</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Time" HREF="time.html"><LINK REL="PREVIOUS" TITLE="SDL_Delay" HREF="sdldelay.html"><LINK REL="NEXT" TITLE="SDL_RemoveTimer" HREF="sdlremovetimer.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdldelay.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlremovetimer.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLADDTIMER" ></A >SDL_AddTimer</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN8482" ></A ><H2 >Name</H2 >SDL_AddTimer -- Add a timer which will call a callback after the specified number of milliseconds has elapsed.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN8485" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN8486" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_TimerID <B CLASS="FSFUNC" >SDL_AddTimer</B ></CODE >(Uint32 interval, SDL_NewTimerCallback callback, void *param);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SDLNEWTIMERCALLBACK" ></A ><H2 >Callback</H2 ><PRE CLASS="PROGRAMLISTING" >/* type definition for the "new" timer callback function */ typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8495" ></A ><H2 >Description</H2 ><P >Adds a callback function to be run after the specified number of milliseconds has elapsed. The callback function is passed the current timer interval and the user supplied parameter from the <TT CLASS="FUNCTION" >SDL_AddTimer</TT > call and returns the next timer interval. If the returned value from the callback is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled.</P ><P >To cancel a currently running timer call <A HREF="sdlremovetimer.html" >SDL_RemoveTimer</A > with the timer ID returned from <TT CLASS="FUNCTION" >SDL_AddTimer</TT >.</P ><P >The timer callback function may run in a different thread than your main program, and so shouldn't call any functions from within itself. You may always call <A HREF="sdlpushevent.html" >SDL_PushEvent</A >, however.</P ><P >The granularity of the timer is platform-dependent, but you should count on it being at least 10 ms as this is the most common number. This means that if you request a 16 ms timer, your callback will run approximately 20 ms later on an unloaded system. If you wanted to set a flag signaling a frame update at 30 frames per second (every 33 ms), you might set a timer for 30 ms (see example below). If you use this function, you need to pass <TT CLASS="LITERAL" >SDL_INIT_TIMER</TT > to <A HREF="sdlinit.html" >SDL_Init</A >.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8507" ></A ><H2 >Return Value</H2 ><P >Returns an ID value for the added timer or <SPAN CLASS="RETURNVALUE" >NULL</SPAN > if there was an error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8511" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >my_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8515" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlremovetimer.html" ><TT CLASS="FUNCTION" >SDL_RemoveTimer</TT ></A >, <A HREF="sdlpushevent.html" ><TT CLASS="FUNCTION" >SDL_PushEvent</TT ></A ></P ></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" ><A HREF="sdldelay.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlremovetimer.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_Delay</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="time.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_RemoveTimer</TD ></TR ></TABLE ></DIV ></BODY ></HTML >