1 /*

     2     SDL - Simple DirectMedia Layer

     3     Copyright (C) 1997-2006 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@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 }