Manual Pages for UNIX Operating System command usage for man SDL_LockSurface

SDL API Reference                              SDL_LockSurface(3)



NAME
     SDL_LockSurface - Lock a surface for directly access.

SYNOPSIS
     #include "SDL.h"

     int SDL_LockSurface(SDL_Surface *surface);

DESCRIPTION
     SDL_LockSurface sets up a surface for directly accessing the
     pixels.     Between    calls    to    SDL_LockSurface    and
     SDL_UnlockSurface, you can write to and read  from  surface-
     >pixels,  using  the pixel format stored in surface->format.
     Once you are done accessing  the  surface,  you  should  use
     SDL_UnlockSurface to release it.

     Not all surfaces require locking.  If  SDL_MUSTLOCK(surface)
     evaluates  to  0, then you can read and write to the surface
     at any time, and the pixel format of the  surface  will  not
     change.

     No operating system or library calls should be made  between
     lock/unlock pairs, as critical system locks may be held dur-
     ing this time.

     It should be noted, that since SDL 1.1.8 surface  locks  are
     recursive.  This  means that you can lock a surface multiple
     times, but each lock must have a match unlock.

         .
         .
         SDL_LockSurface( surface );
         .
         /* Surface is locked */
         /* Direct pixel access on surface here */
         .
         SDL_LockSurface( surface );
         .
         /* More direct pixel access on surface */
         .
         SDL_UnlockSurface( surface );
         /* Surface is still locked */
         /* Note: Is versions < 1.1.8, the surface would have been */
         /* no longer locked at this stage                         */
         .
         SDL_UnlockSurface( surface );
         /* Surface is now unlocked */
         .
         .

RETURN VALUE




SDL            Last change: Tue 11 Sep 2001, 23:01              1






SDL API Reference                              SDL_LockSurface(3)



     SDL_LockSurface returns 0, or -1 if the surface couldn't  be
     locked.

SEE ALSO
     SDL_UnlockSurface


















































SDL            Last change: Tue 11 Sep 2001, 23:01              2