sdl-ios-xcode: src/thread/nds/SDL

annotate src/thread/nds/SDL_syscond.c @ 3483:a54df8e52333

Made the comment actually mean something. :)

author	Sam Lantinga <slouken@libsdl.org>
date	Sun, 22 Nov 2009 20:00:00 +0000
parents	99210400e8b9
children	f7b03b6838cb

rev	line source
2735 204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	1 /*
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	2 SDL - Simple DirectMedia Layer
2859 99210400e8b9 Updated copyright date Sam Lantinga <slouken@libsdl.org> parents: 2735 diff changeset	3 Copyright (C) 1997-2009 Sam Lantinga
2735 204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	4
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	5 This library is free software; you can redistribute it and/or
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	6 modify it under the terms of the GNU Library General Public
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	7 License as published by the Free Software Foundation; either
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	8 version 2 of the License, or (at your option) any later version.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	9
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	10 This library is distributed in the hope that it will be useful,
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	11 but WITHOUT ANY WARRANTY; without even the implied warranty of
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	13 Library General Public License for more details.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	14
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	15 You should have received a copy of the GNU Library General Public
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	16 License along with this library; if not, write to the Free
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	18
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	19 Sam Lantinga
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	20 slouken@devolution.com
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	21 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	22
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	23 #ifdef SAVE_RCSID
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	24 static char rcsid =
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	25 "@(#) $Id: SDL_syscond.c,v 1.2 2001/04/26 16:50:18 hercules Exp $";
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	26 #endif
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	27
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	28 /* An implementation of condition variables using semaphores and mutexes */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	29 /*
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	30 This implementation borrows heavily from the BeOS condition variable
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	31 implementation, written by Christopher Tate and Owen Smith. Thanks!
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	32 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	33
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	34 #include <stdio.h>
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	35 #include <stdlib.h>
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	36
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	37 #include "SDL_error.h"
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	38 #include "SDL_thread.h"
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	39
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	40 struct SDL_cond
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	41 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	42 SDL_mutex *lock;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	43 int waiting;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	44 int signals;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	45 SDL_sem *wait_sem;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	46 SDL_sem *wait_done;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	47 };
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	48
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	49 /* Create a condition variable */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	50 SDL_cond *
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	51 SDL_CreateCond(void)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	52 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	53 SDL_cond *cond;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	54
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	55 cond = (SDL_cond *) malloc(sizeof(SDL_cond));
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	56 if (cond) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	57 cond->lock = SDL_CreateMutex();
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	58 cond->wait_sem = SDL_CreateSemaphore(0);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	59 cond->wait_done = SDL_CreateSemaphore(0);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	60 cond->waiting = cond->signals = 0;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	61 if (!cond->lock \|\| !cond->wait_sem \|\| !cond->wait_done) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	62 SDL_DestroyCond(cond);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	63 cond = NULL;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	64 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	65 } else {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	66 SDL_OutOfMemory();
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	67 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	68 return (cond);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	69 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	70
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	71 /* Destroy a condition variable */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	72 void
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	73 SDL_DestroyCond(SDL_cond * cond)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	74 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	75 if (cond) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	76 if (cond->wait_sem) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	77 SDL_DestroySemaphore(cond->wait_sem);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	78 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	79 if (cond->wait_done) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	80 SDL_DestroySemaphore(cond->wait_done);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	81 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	82 if (cond->lock) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	83 SDL_DestroyMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	84 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	85 free(cond);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	86 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	87 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	88
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	89 /* Restart one of the threads that are waiting on the condition variable */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	90 int
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	91 SDL_CondSignal(SDL_cond * cond)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	92 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	93 if (!cond) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	94 SDL_SetError("Passed a NULL condition variable");
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	95 return -1;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	96 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	97
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	98 /* If there are waiting threads not already signalled, then
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	99 signal the condition and wait for the thread to respond.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	100 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	101 SDL_LockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	102 if (cond->waiting > cond->signals) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	103 ++cond->signals;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	104 SDL_SemPost(cond->wait_sem);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	105 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	106 SDL_SemWait(cond->wait_done);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	107 } else {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	108 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	109 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	110
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	111 return 0;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	112 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	113
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	114 /* Restart all threads that are waiting on the condition variable */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	115 int
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	116 SDL_CondBroadcast(SDL_cond * cond)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	117 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	118 if (!cond) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	119 SDL_SetError("Passed a NULL condition variable");
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	120 return -1;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	121 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	122
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	123 /* If there are waiting threads not already signalled, then
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	124 signal the condition and wait for the thread to respond.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	125 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	126 SDL_LockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	127 if (cond->waiting > cond->signals) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	128 int i, num_waiting;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	129
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	130 num_waiting = (cond->waiting - cond->signals);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	131 cond->signals = cond->waiting;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	132 for (i = 0; i < num_waiting; ++i) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	133 SDL_SemPost(cond->wait_sem);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	134 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	135 /* Now all released threads are blocked here, waiting for us.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	136 Collect them all (and win fabulous prizes!) :-)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	137 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	138 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	139 for (i = 0; i < num_waiting; ++i) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	140 SDL_SemWait(cond->wait_done);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	141 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	142 } else {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	143 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	144 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	145
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	146 return 0;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	147 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	148
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	149 /* Wait on the condition variable for at most 'ms' milliseconds.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	150 The mutex must be locked before entering this function!
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	151 The mutex is unlocked during the wait, and locked again after the wait.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	152
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	153 Typical use:
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	154
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	155 Thread A:
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	156 SDL_LockMutex(lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	157 while ( ! condition ) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	158 SDL_CondWait(cond);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	159 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	160 SDL_UnlockMutex(lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	161
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	162 Thread B:
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	163 SDL_LockMutex(lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	164 ...
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	165 condition = true;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	166 ...
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	167 SDL_UnlockMutex(lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	168 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	169 int
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	170 SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	171 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	172 int retval;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	173
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	174 if (!cond) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	175 SDL_SetError("Passed a NULL condition variable");
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	176 return -1;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	177 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	178
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	179 /* Obtain the protection mutex, and increment the number of waiters.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	180 This allows the signal mechanism to only perform a signal if there
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	181 are waiting threads.
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	182 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	183 SDL_LockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	184 ++cond->waiting;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	185 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	186
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	187 /* Unlock the mutex, as is required by condition variable semantics */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	188 SDL_UnlockMutex(mutex);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	189
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	190 /* Wait for a signal */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	191 if (ms == SDL_MUTEX_MAXWAIT) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	192 retval = SDL_SemWait(cond->wait_sem);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	193 } else {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	194 retval = SDL_SemWaitTimeout(cond->wait_sem, ms);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	195 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	196
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	197 /* Let the signaler know we have completed the wait, otherwise
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	198 the signaler can race ahead and get the condition semaphore
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	199 if we are stopped between the mutex unlock and semaphore wait,
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	200 giving a deadlock. See the following URL for details:
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	201 http://www-classic.be.com/aboutbe/benewsletter/volume_III/Issue40.html
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	202 */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	203 SDL_LockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	204 if (cond->signals > 0) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	205 /* If we timed out, we need to eat a condition signal */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	206 if (retval > 0) {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	207 SDL_SemWait(cond->wait_sem);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	208 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	209 /* We always notify the signal thread that we are done */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	210 SDL_SemPost(cond->wait_done);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	211
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	212 /* Signal handshake complete */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	213 --cond->signals;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	214 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	215 --cond->waiting;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	216 SDL_UnlockMutex(cond->lock);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	217
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	218 /* Lock the mutex, as is required by condition variable semantics */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	219 SDL_LockMutex(mutex);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	220
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	221 return retval;
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	222 }
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	223
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	224 /* Wait on the condition variable forever */
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	225 int
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	226 SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	227 {
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	228 return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
204be4fc2726 Final merge of Google Summer of Code 2008 work... Sam Lantinga <slouken@libsdl.org> parents: diff changeset	229 }

Mercurial > sdl-ios-xcode

annotate src/thread/nds/SDL_syscond.c @ 3483:a54df8e52333