SDL_audiomem.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
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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
Sam Lantinga
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slouken@libsdl.org
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*/
#ifdef SAVE_RCSID
static char rcsid =
"@(#) $Id$";
#endif
/* Functions to allocate audio buffer memory, shareable across threads
(necessary because SDL audio emulates threads with fork()
*/
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#include <stdlib.h>
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#ifdef FORK_HACK
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stddef.h>
#endif
#include "SDL_audiomem.h"
/* Allocate memory that will be shared between threads (freed on exit) */
void *SDL_AllocAudioMem(int size)
{
void *chunk;
#ifdef FORK_HACK
int semid;
/* Create and get the address of a shared memory segment */
semid = shmget(IPC_PRIVATE, size, (IPC_CREAT|0600));
if ( semid < 0 ) {
return(NULL);
}
chunk = shmat(semid, NULL, 0);
/* Set the segment for deletion when it is detatched */
shmctl(semid, IPC_RMID, NULL); /* Delets semid if shmat() fails */
#else
chunk = malloc(size);
#endif
return((void *)chunk);
}
void SDL_FreeAudioMem(void *chunk)
{
#ifdef FORK_HACK
shmdt(chunk);
#else
free(chunk);
#endif
}