Mercurial > sdl-ios-xcode
view src/thread/dc/SDL_sysmutex.c @ 571:8e3ce997621c
Date: Thu, 16 Jan 2003 13:48:31 +0200
From: "Mike Gorchak"
Subject: All QNX patches
whole patches concerning QNX. Almost all code has been rewritten by Julian
and me. Added initial support for hw overlays in QNX and many many others
fixes.
P.S. This patches has been reviewed by Dave Rempel from QSSL and included in
SDL 1.2.5 distribution, which coming on 3rd party CD for newest 6.2.1
version of QNX, which will be available soon.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 20 Jan 2003 01:38:37 +0000 |
parents | dad72daf44b3 |
children | b8d311d90021 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA BERO bero@geocities.co.jp based on generic/SDL_sysmutex.c Sam Lantinga slouken@libsdl.org */ #ifdef SAVE_RCSID static char rcsid = "@(#) $Id$"; #endif /* An implementation of mutexes using semaphores */ #include <stdio.h> #include <stdlib.h> #include "SDL_error.h" #include "SDL_thread.h" #include "SDL_systhread_c.h" #include <arch/spinlock.h> struct SDL_mutex { int recursive; Uint32 owner; spinlock_t mutex; }; /* Create a mutex */ SDL_mutex *SDL_CreateMutex(void) { SDL_mutex *mutex; /* Allocate mutex memory */ mutex = (SDL_mutex *)malloc(sizeof(*mutex)); if ( mutex ) { spinlock_init(&mutex->mutex); mutex->recursive = 0; mutex->owner = 0; } else { SDL_OutOfMemory(); } return mutex; } /* Free the mutex */ void SDL_DestroyMutex(SDL_mutex *mutex) { if ( mutex ) { free(mutex); } } /* Lock the semaphore */ int SDL_mutexP(SDL_mutex *mutex) { #ifdef DISABLE_THREADS return 0; #else Uint32 this_thread; if ( mutex == NULL ) { SDL_SetError("Passed a NULL mutex"); return -1; } this_thread = SDL_ThreadID(); if ( mutex->owner == this_thread ) { ++mutex->recursive; } else { /* The order of operations is important. We set the locking thread id after we obtain the lock so unlocks from other threads will fail. */ spinlock_lock(&mutex->mutex); mutex->owner = this_thread; mutex->recursive = 0; } return 0; #endif /* DISABLE_THREADS */ } /* Unlock the mutex */ int SDL_mutexV(SDL_mutex *mutex) { #ifdef DISABLE_THREADS return 0; #else if ( mutex == NULL ) { SDL_SetError("Passed a NULL mutex"); return -1; } /* If we don't own the mutex, we can't unlock it */ if ( SDL_ThreadID() != mutex->owner ) { SDL_SetError("mutex not owned by this thread"); return -1; } if ( mutex->recursive ) { --mutex->recursive; } else { /* The order of operations is important. First reset the owner so another thread doesn't lock the mutex and set the ownership before we reset it, then release the lock semaphore. */ mutex->owner = 0; spinlock_unlock(&mutex->mutex); } return 0; #endif /* DISABLE_THREADS */ }