view docs/html/sdlflip.html @ 4355:9b464226e541 SDL-1.2

Fixed bug #855 Ludwig Nussel 2009-10-18 06:31:52 PDT an mprotect call was added to fix bug 528. However that results in a buffer that allows writing and code execution. Ie the no-execute security features of modern operating systems are defeated this way. Two mprotect calls are needed. One to make the buffer executable but not writeable when done and another one to make the buffer writeable again if the content needs to be changed.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 18 Oct 2009 17:31:37 +0000
parents 355632dca928
children
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>SDL_Flip</TITLE
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><H1
><A
NAME="SDLFLIP"
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>SDL_Flip</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1426"
></A
><H2
>Name</H2
>SDL_Flip&nbsp;--&nbsp;Swaps screen buffers</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1429"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1430"
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_Flip</B
></CODE
>(SDL_Surface *screen);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1436"
></A
><H2
>Description</H2
><P
>On hardware that supports double-buffering, this function sets up a flip
and returns.  The hardware will wait for vertical retrace, and then swap
video buffers before the next video surface blit or lock will return.
On hardware that doesn't support double-buffering, this is equivalent
to calling <A
HREF="sdlupdaterect.html"
>SDL_UpdateRect</A
><TT
CLASS="PARAMETER"
><I
>(screen, 0, 0, 0, 0)</I
></TT
></P
><P
>The <TT
CLASS="LITERAL"
>SDL_DOUBLEBUF</TT
> flag must have been passed to 
<A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>,
 when
setting the video mode for this function to perform hardware flipping.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1444"
></A
><H2
>Return Value</H2
><P
>This function returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> if successful, or 
<SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1449"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>,
<A
HREF="sdlupdaterect.html"
><TT
CLASS="FUNCTION"
>SDL_UpdateRect</TT
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
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