Mercurial > sdl-ios-xcode

view docs/html/sdlpollevent.html @ 968:4675910b0b7b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 12 Nov 2004 21:39:04 +0000
parents 355632dca928
children
line wrap: on
line source

<HTML
><HEAD
><TITLE
>SDL_PollEvent</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="Event Functions."
HREF="eventfunctions.html"><LINK
REL="PREVIOUS"
TITLE="SDL_PeepEvents"
HREF="sdlpeepevents.html"><LINK
REL="NEXT"
TITLE="SDL_WaitEvent"
HREF="sdlwaitevent.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="sdlpeepevents.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlwaitevent.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLPOLLEVENT"
></A
>SDL_PollEvent</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN5472"
></A
><H2
>Name</H2
>SDL_PollEvent&nbsp;--&nbsp;Polls for currently pending events.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN5475"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN5476"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_PollEvent</B
></CODE
>(SDL_Event *event);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN5482"
></A
><H2
>Description</H2
><P
>Polls for currently pending events, and returns <SPAN
CLASS="RETURNVALUE"
>1</SPAN
> 
if there are any pending events, or <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> if there 
are none available.  </P
><P
>If <TT
CLASS="PARAMETER"
><I
>event</I
></TT
> is not <TT
CLASS="LITERAL"
>NULL</TT
>, the next 
event is removed from the queue and stored in that area.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN5490"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>SDL_Event event; /* Event structure */

.
.
.
/* Check for events */
while(SDL_PollEvent(&#38;event)){  /* Loop until there are no events left on the queue */
  switch(event.type){  /* Process the appropiate event type */
    case SDL_KEYDOWN:  /* Handle a KEYDOWN event */         
      printf("Oh! Key press\n");
      break;
    case SDL_MOUSEMOTION:
      .
      .
      .
    default: /* Report an unhandled event */
      printf("I don't know what this event is!\n");
  }
}</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN5494"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
>,
<A
HREF="sdlwaitevent.html"
><TT
CLASS="FUNCTION"
>SDL_WaitEvent</TT
></A
>,
<A
HREF="sdlpeepevents.html"
><TT
CLASS="FUNCTION"
>SDL_PeepEvents</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="sdlpeepevents.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="sdlwaitevent.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_PeepEvents</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="eventfunctions.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_WaitEvent</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>