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Fixed bug #166 From the autoconf obsolete macros documentation: Macro: AC_CANONICAL_SYSTEM Determine the system type and set output variables to the names of the canonical system types. See section Getting the Canonical System Type, for details about the variables this macro sets. The user is encouraged to use either AC_CANONICAL_BUILD, or AC_CANONICAL_HOST, or AC_CANONICAL_TARGET, depending on the needs. Using AC_CANONICAL_TARGET is enough to run the two other macros. From the documentation for the canonical environments: case $target in i386-*-mach* | i386-*-gnu*) obj_format=aout emulation=mach bfd_gas=yes ;; i960-*-bout) obj_format=bout ;; esac Note that the above example uses $target because it's taken from a tool which can be built on some architecture ($build), run on another ($host), but yet handle data for a third architecture ($target). Such tools are usually part of a compiler suite, they generate code for a specific $target. However $target should be meaningless for most packages. If you want to base a decision on the system where your program will be run, make sure you use the $host variable.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 19 Mar 2006 05:27:22 +0000
parents 355632dca928
children 85cbe9c892f4
line wrap: on
line source

<HTML
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><TITLE
>SDL_Event</TITLE
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><H1
><A
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>SDL_Event</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN3711"
></A
><H2
>Name</H2
>SDL_Event&nbsp;--&nbsp;General event structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3714"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef union{
  Uint8 type;
  SDL_ActiveEvent active;
  SDL_KeyboardEvent key;
  SDL_MouseMotionEvent motion;
  SDL_MouseButtonEvent button;
  SDL_JoyAxisEvent jaxis;
  SDL_JoyBallEvent jball;
  SDL_JoyHatEvent jhat;
  SDL_JoyButtonEvent jbutton;
  SDL_ResizeEvent resize;
  SDL_ExposeEvent expose;
  SDL_QuitEvent quit;
  SDL_UserEvent user;
  SDL_SywWMEvent syswm;
} SDL_Event;</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3717"
></A
><H2
>Structure Data</H2
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3719"
></A
><P
></P
><TABLE
BORDER="0"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>The type of event</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>active</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlactiveevent.html"
>Activation event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>key</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlkeyboardevent.html"
>Keyboard event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>motion</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlmousemotionevent.html"
>Mouse motion event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>button</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlmousebuttonevent.html"
>Mouse button event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>jaxis</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyaxisevent.html"
>Joystick axis motion event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>jball</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyballevent.html"
>Joystick trackball motion event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>jhat</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyhatevent.html"
>Joystick hat motion event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>jbutton</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoybuttonevent.html"
>Joystick button event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>resize</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlresizeevent.html"
>Application window resize event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>expose</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlexposeevent.html"
>Application window expose event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>quit</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlquitevent.html"
>Application quit request event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>user</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdluserevent.html"
>User defined event</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>syswm</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlsyswmevent.html"
>Undefined window manager event</A
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3791"
></A
><H2
>Description</H2
><P
>The <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> union is the core to all event handling is SDL, its probably the most important structure after <SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
>. <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> is a union of all event structures used in SDL, using it is a simple matter of knowing which union member relates to which event <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
>.</P
><P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3799"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><THEAD
><TR
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Event <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
></TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Event Structure</TH
></TR
></THEAD
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
><TT
CLASS="LITERAL"
>SDL_ACTIVEEVENT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
><A
HREF="sdlactiveevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_ActiveEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_KEYDOWN/UP</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlkeyboardevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_KeyboardEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_MOUSEMOTION</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlmousemotionevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_MouseMotionEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_MOUSEBUTTONDOWN/UP</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlmousebuttonevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_MouseButtonEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_JOYAXISMOTION</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyaxisevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_JoyAxisEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_JOYBALLMOTION</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyballevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_JoyBallEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_JOYHATMOTION</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoyhatevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_JoyHatEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_JOYBUTTONDOWN/UP</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdljoybuttonevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_JoyButtonEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_QUIT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlquitevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_QuitEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SYSWMEVENT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlsyswmevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_SysWMEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_VIDEORESIZE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlresizeevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_ResizeEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_VIDEOEXPOSE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdlexposeevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_ExposeEvent</SPAN
></A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_USEREVENT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><A
HREF="sdluserevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_UserEvent</SPAN
></A
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3885"
></A
><H2
>Use</H2
><P
>The <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> structure has two uses</P
><P
></P
><UL
COMPACT="COMPACT"
><LI
><P
>Reading events on the event queue</P
></LI
><LI
><P
>Placing events on the event queue</P
></LI
></UL
><P
>Reading events from the event queue is done with either <A
HREF="sdlpollevent.html"
><TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
></A
> or <A
HREF="sdlpeepevents.html"
><TT
CLASS="FUNCTION"
>SDL_PeepEvents</TT
></A
>. We'll use <TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
> and step through an example.</P
><P
>First off, we create an empty <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> structure.
<PRE
CLASS="PROGRAMLISTING"
>SDL_Event test_event;</PRE
>
<TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
> removes the next event from the event queue, if there are no events on the queue it returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> otherwise it returns <SPAN
CLASS="RETURNVALUE"
>1</SPAN
>. We use a <TT
CLASS="FUNCTION"
>while</TT
> loop to process each event in turn.
<PRE
CLASS="PROGRAMLISTING"
>while(SDL_PollEvent(&#38;test_event)) {</PRE
>
The <TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
> function take a pointer to an <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
> structure that is to be filled with event information. We know that if <TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
> removes an event from the queue then the event information will be placed in our <SPAN
CLASS="STRUCTNAME"
>test_event</SPAN
> structure, but we also know that the <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>type</I
></SPAN
> of event will be placed in the <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> member of <SPAN
CLASS="STRUCTNAME"
>test_event</SPAN
>. So to handle each event <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> seperately we use a <TT
CLASS="FUNCTION"
>switch</TT
> statement.
<PRE
CLASS="PROGRAMLISTING"
>  switch(test_event.type) {</PRE
>
We need to know what kind of events we're looking for <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>and</I
></SPAN
> the event <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
>'s of those events. So lets assume we want to detect where the user is moving the mouse pointer within our application. We look through our event types and notice that <TT
CLASS="LITERAL"
>SDL_MOUSEMOTION</TT
> is, more than likely, the event we're looking for. A little <A
HREF="sdlmousemotionevent.html"
>more</A
> research tells use that <TT
CLASS="LITERAL"
>SDL_MOUSEMOTION</TT
> events are handled within the <A
HREF="sdlmousemotionevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_MouseMotionEvent</SPAN
></A
> structure which is the <TT
CLASS="STRUCTFIELD"
><I
>motion</I
></TT
> member of <SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
>. We can check for the <TT
CLASS="LITERAL"
>SDL_MOUSEMOTION</TT
> event <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> within our <TT
CLASS="FUNCTION"
>switch</TT
> statement like so:
<PRE
CLASS="PROGRAMLISTING"
>    case SDL_MOUSEMOTION:</PRE
>
All we need do now is read the information out of the <TT
CLASS="STRUCTFIELD"
><I
>motion</I
></TT
> member of <SPAN
CLASS="STRUCTNAME"
>test_event</SPAN
>.
<PRE
CLASS="PROGRAMLISTING"
>      printf("We got a motion event.\n");
      printf("Current mouse position is: (%d, %d)\n", test_event.motion.x, test_event.motion.y);
      break;
    default:
      printf("Unhandled Event!\n");
      break;
  }
}
printf("Event queue empty.\n");</PRE
></P
><P
>It is also possible to push events onto the event queue and so use it as a two-way communication path. Both <A
HREF="sdlpushevent.html"
><TT
CLASS="FUNCTION"
>SDL_PushEvent</TT
></A
> and <A
HREF="sdlpeepevents.html"
><TT
CLASS="FUNCTION"
>SDL_PeepEvents</TT
></A
> allow you to place events onto the event queue. This is usually used to place a <TT
CLASS="LITERAL"
>SDL_USEREVENT</TT
> on the event queue, however you could use it to post fake input events if you wished. Creating your own events is a simple matter of choosing the event type you want, setting the <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> member and filling the appropriate member structure with information.
<PRE
CLASS="PROGRAMLISTING"
>SDL_Event user_event;

user_event.type=SDL_USEREVENT;
user_event.user.code=2;
user_event.user.data1=NULL;
user_event.user.data2=NULL;
SDL_PushEvent(&#38;user_event);</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3942"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlpollevent.html"
><TT
CLASS="FUNCTION"
>SDL_PollEvent</TT
></A
>,
<A
HREF="sdlpushevent.html"
><TT
CLASS="FUNCTION"
>SDL_PushEvent</TT
></A
>,
<A
HREF="sdlpeepevents.html"
><TT
CLASS="FUNCTION"
>SDL_PeepEvents</TT
></A
></P
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