Mercurial > sdl-ios-xcode

view docs/man3/SDL_SemWait.3 @ 2359:b70b96e615d2 gsoc2008_iphone

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
These files are the OpenGL ES render driver. You should be able to use them on any platform that supports OpenGL ES -- not just iPhone. The driver is based off the OpenGL render driver. There are a few differences between OpenGL and OpenGL ES that present difficulties for this driver: - OpenGL ES does NOT support many pixel formats (for example, no GL_BGR). Also, when using texture functions format and internalFormat must be the same -- this means 32 bit packed formats like SDL_PIXELFORMAT_BGR888 cannot be automatically converted to GL_RGB (which is 24bpp). - OpenGL ES doesn't have GL_PACK_ROW_LENGTH, which means data must be reformatted before uploading changes to dirty rects. This change has been added. - OpenGL ES doesn't support paletted textures, though there is an extension. I'm looking into this. Some other notable differences: - OpenGL ES has an extension called GL_OES_draw_texture which allows for quicker 2D sprite-type drawing. I use this in GL_RenderCopy when it is available. The iPhone supports the extension, but the iPhone Simulator does not (presently). - No glBegin() / glEnd() and no GL_QUADS! I'm using glDrawArrays with GL_TRIANGLE_STRIP instead!
author Holmes Futrell <hfutrell@umail.ucsb.edu>
date Thu, 17 Jul 2008 23:31:42 +0000
parents 546f7c1eb755
children 1238da4a7112
line wrap: on
line source

.TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SemWait \- Lock a semaphore and suspend the thread if the semaphore value is zero\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
#include "SDL_thread\&.h"
.sp
\fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_SemWait()\fP suspends the calling thread until either the semaphore pointed to by \fBsem\fR has a positive value, the call is interrupted by a signal or error\&. If the call is successful it will atomically decrement the semaphore value\&.
.PP
After \fBSDL_SemWait()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&.
.SH "RETURN VALUE"
.PP
Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWif (SDL_SemWait(my_sem) == -1) {
        return WAIT_FAILED;
}

\&.\&.\&.

SDL_SemPost(my_sem);\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00