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      1 /*
      2     SDL - Simple DirectMedia Layer
      3     Copyright (C) 1997-2012 Sam Lantinga
      4 
      5     This library is free software; you can redistribute it and/or
      6     modify it under the terms of the GNU Lesser General Public
      7     License as published by the Free Software Foundation; either
      8     version 2.1 of the License, or (at your option) any later version.
      9 
     10     This library is distributed in the hope that it will be useful,
     11     but WITHOUT ANY WARRANTY; without even the implied warranty of
     12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13     Lesser General Public License for more details.
     14 
     15     You should have received a copy of the GNU Lesser General Public
     16     License along with this library; if not, write to the Free Software
     17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
     18 
     19     Sam Lantinga
     20     slouken (at) libsdl.org
     21 */
     22 #include "SDL_config.h"
     23 
     24 /* Mutex functions using the OS/2 API */
     25 
     26 #define INCL_DOSERRORS
     27 #define INCL_DOSSEMAPHORES
     28 #include <os2.h>
     29 
     30 #include "SDL_mutex.h"
     31 
     32 
     33 struct SDL_mutex {
     34 	HMTX hmtxID;
     35 };
     36 
     37 /* Create a mutex */
     38 DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void)
     39 {
     40   SDL_mutex *mutex;
     41   APIRET ulrc;
     42 
     43   /* Allocate mutex memory */
     44   mutex = (SDL_mutex *)SDL_malloc(sizeof(*mutex));
     45   if (mutex)
     46   {
     47     /* Create the mutex, with initial value signaled */
     48     ulrc = DosCreateMutexSem(NULL,                  // Create unnamed semaphore
     49                              &(mutex->hmtxID),      // Pointer to handle
     50                              0L,                    // Flags: create it private (not shared)
     51                              FALSE);                // Initial value: unowned
     52     if (ulrc!=NO_ERROR)
     53     {
     54       SDL_SetError("Couldn't create mutex");
     55       SDL_free(mutex);
     56       mutex = NULL;
     57     }
     58   } else {
     59     SDL_OutOfMemory();
     60   }
     61   return(mutex);
     62 }
     63 
     64 /* Free the mutex */
     65 DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex)
     66 {
     67   if ( mutex )
     68   {
     69     if ( mutex->hmtxID )
     70     {
     71       DosCloseMutexSem(mutex->hmtxID);
     72       mutex->hmtxID = 0;
     73     }
     74     SDL_free(mutex);
     75   }
     76 }
     77 
     78 /* Lock the mutex */
     79 DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex)
     80 {
     81   if ( mutex == NULL )
     82   {
     83     SDL_SetError("Passed a NULL mutex");
     84     return -1;
     85   }
     86   if ( DosRequestMutexSem(mutex->hmtxID, SEM_INDEFINITE_WAIT) != NO_ERROR )
     87   {
     88     SDL_SetError("Couldn't wait on mutex");
     89     return -1;
     90   }
     91   return(0);
     92 }
     93 
     94 /* Unlock the mutex */
     95 DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex)
     96 {
     97   if ( mutex == NULL )
     98   {
     99     SDL_SetError("Passed a NULL mutex");
    100     return -1;
    101   }
    102   if ( DosReleaseMutexSem(mutex->hmtxID) != NO_ERROR )
    103   {
    104     SDL_SetError("Couldn't release mutex");
    105     return -1;
    106   }
    107   return(0);
    108 }
    109