Mercurial > sdl-ios-xcode
view test/testsem.c @ 968:4675910b0b7b
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
From: Hannu Savolainen
Subject: Re: SDL uses obsolete OSS features
I did some work on getting OSS to work better with SDL. There have been
some problems with select which should be fixed now.
I'm having some problems in understanding what is the purpose of the
DSP_WaitAudio() routine. I added a return to the very beginning of this
routine and commendted out the define for USE_BLOCKING_WRITES. At least
lbreakout2 seems to work as well as earlier. The latencies are the same.
An ordinary blocking write does exactly the same thing than DSP_WaitAudio
does. So I would recommend using the USE_BLOCKING_WRITES approach and
removing everything from the DSP_WaitAudio routine. Also enabling
USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because
you don't need to handle the partial writes (the do-while loop).
Attached is a patch against SDL-1.2.7. After these changes SDL will use
OSS as it's designed to be used (make it as simple as possible). This code
should work with all OSS implementations because it uses only the very
fundamental features that have been there since the jurassic times.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 12 Nov 2004 21:39:04 +0000 |
parents | 74212992fb08 |
children | be9c9c8f6d53 |
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/* Simple test of the SDL semaphore code */ #include <stdio.h> #include <stdlib.h> #include <signal.h> #include "SDL.h" #include "SDL_thread.h" #define NUM_THREADS 10 static SDL_sem *sem; int alive = 1; int ThreadFunc(void *data) { while ( alive ) { SDL_SemWait(sem); fprintf(stderr, "Thread number %d has got the semaphore (value = %d)!\n", (int)data, SDL_SemValue(sem)); SDL_Delay(200); SDL_SemPost(sem); fprintf(stderr, "Thread number %d has released the semaphore (value = %d)!\n", (int)data, SDL_SemValue(sem)); SDL_Delay(1); /* For the scheduler */ } printf("Thread number %d exiting.\n", (int)data); return 0; } static void killed(int sig) { alive = 0; } int main(int argc, char **argv) { SDL_Thread *threads[NUM_THREADS]; int i, init_sem; if(argc < 2) { fprintf(stderr,"Usage: %s init_value\n", argv[0]); exit(1); } /* Load the SDL library */ if ( SDL_Init(0) < 0 ) { fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError()); exit(1); } atexit(SDL_Quit); signal(SIGTERM, killed); signal(SIGINT, killed); init_sem = atoi(argv[1]); sem = SDL_CreateSemaphore(init_sem); printf("Running %d threads, semaphore value = %d\n", NUM_THREADS, init_sem); /* Create all the threads */ for( i = 0; i < NUM_THREADS; ++i ) { threads[i] = SDL_CreateThread(ThreadFunc, (void*)i); } /* Wait 10 seconds */ SDL_Delay(10 * 1000); /* Wait for all threads to finish */ printf("Waiting for threads to finish\n"); alive = 0; for( i = 0; i < NUM_THREADS; ++i ) { SDL_WaitThread(threads[i], NULL); } printf("Finished waiting for threads\n"); SDL_DestroySemaphore(sem); return(0); }