view docs/man3/SDL_LockSurface.3 @ 1438:1f4f09641645

Date: Sun, 26 Feb 2006 11:25:09 +0900 From: Hayashi Naoyuki Subject: Re: [SDL] CVS stable again, please update SDL ports Some problems are caused on Tru64 UNIX. If applying SDL12-osf1.path, these problems are fixed. 1. configure-script say "recursive mutexes... no" and "pthread semaphores... no". checking for pthreads... yes checking for recursive mutexes... no checking for pthread semaphores... no This is because it compiled without pthread_cflags and pthread_lib when checking recursive mutexes and pthread semaphores. 2. Compiling src/audio/mme/SDL_mmeaudio.c fails. cc: Severe: ./src/audio/mme/SDL_mmeaudio.c, line 25: Cannot find file <mme_api.h> specified in #include directive. (noinclfilef) #include <mme_api.h> -^ This is because BUILD_CFLAGS is wrong. 3. Compiling src/cdrom/osf/SDL_syscdrom.c fails. cc: Warning: ./src/cdrom/osf/SDL_syscdrom.c, line 176: Too few actual parameters in the invocation of the macro "SDL_stack_alloc". (toofewactuals) cdpath = SDL_stack_alloc(len); ------------------------------------^ cc: Error: ./src/cdrom/osf/SDL_syscdrom.c, line 176: Invalid expression. (badexpr) cdpath = SDL_stack_alloc(len); -----------------^ SDL_stack_alloc is defined in include/SDL_stdinc.h. #define SDL_stack_alloc(type, count) (type*)alloca(sizeof(type)*count) 4. Linking fails if running configure with --enable-x11-shared=yes. /usr/ccs/bin/ld: Warning: Unresolved: p_XData32 5. Compiling src/video/x11/SDL_x11dyn.c fails if running configure with --enable-x11-shared=no. cc: Error: ./src/video/x11/SDL_x11sym.h, line 149: In this statement, "_SmtBufferOverflow" is not declared. (undeclared) SDL_X11_SYM(1,void,_SmtBufferOverflow,(Display *dpy,register smtDisplayPtr)) ^ cc: Error: ./src/video/x11/SDL_x11sym.h, line 150: In this statement, "_SmtBufferOverflow" is not declared. (undeclared) SDL_X11_SYM(1,void,_SmtBufferOverflow,(Display *dpy,register smtDisplayPtr)) ^ cc: Error: ./src/video/x11/SDL_x11sym.h, line 150: In this statement, "_SmtIpError" is not declared. (undeclared) SDL_X11_SYM(1,void,_SmtIpError,(Display *dpy,register smtDisplayPtr, int)) ^
author Sam Lantinga <slouken@libsdl.org>
date Sun, 26 Feb 2006 04:54:01 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_LockSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_LockSurface\- Lock a surface for directly access\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_LockSurface\fP\fR(\fBSDL_Surface *surface\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_LockSurface\fP sets up a surface for directly accessing the pixels\&. Between calls to \fBSDL_LockSurface\fP and \fBSDL_UnlockSurface\fP, you can write to and read from \fBsurface->\fBpixels\fR\fR, using the pixel format stored in \fBsurface->\fBformat\fR\fR\&. Once you are done accessing the surface, you should use \fBSDL_UnlockSurface\fP to release it\&.
.PP
Not all surfaces require locking\&. If \fBSDL_MUSTLOCK\fP(\fBsurface\fR) evaluates to \fB0\fR, then you can read and write to the surface at any time, and the pixel format of the surface will not change\&. 
.PP
No operating system or library calls should be made between lock/unlock pairs, as critical system locks may be held during this time\&.
.PP
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\&. 
.PP
.nf
\f(CW    \&.
    \&.
    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 */
    \&.
    \&.\fR
.fi
.PP
.SH "RETURN VALUE"
.PP
\fBSDL_LockSurface\fP returns \fB0\fR, or \fB-1\fR if the surface couldn\&'t be locked\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_UnlockSurface\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01