ACE/apps/JAWS/clients/WebSTONE/src/nsapi-includes/base/sem.h

   1 /*
   2  * Copyright (c) 1994, 1995.  Netscape Communications Corporation.  All
   3  * rights reserved.
   4  *
   5  * Use of this software is governed by the terms of the license agreement for
   6  * the Netscape Communications or Netscape Comemrce Server between the
   7  * parties.
   8  */
   9
  10
  11 /* ------------------------------------------------------------------------ */
  12
  13
  14 /*
  15  * sem.h: Attempt to provide multi-process semaphores across platforms
  16  *
  17  * Rob McCool
  18  */
  19
  20
  21 #ifndef SEM_H
  22 #define SEM_H
  23
  24 #include "systems.h"
  25
  26
  27 /* All of the implementations currently use int as the semaphore type */
  28 #ifdef SEM_WIN32
  29 typedef HANDLE SEMAPHORE;
  30 #define SEM_ERROR 0
  31 /* That oughta hold them (I hope) */
  32 #define SEM_MAXVALUE 32767
  33
  34 #else /* ! SEM_WIN32 */
  35 typedef int SEMAPHORE;
  36 #define SEM_ERROR -1
  37 #endif /* SEM_WIN32 */
  38
  39 /*
  40  * sem_init creates a semaphore using the given name and unique
  41  * identification number. filename should be a file accessible to the
  42  * process. Returns SEM_ERROR on error.
  43  */
  44
  45 SEMAPHORE sem_init(char *name, int number);
  46
  47 /*
  48  * sem_terminate de-allocates the given semaphore.
  49  */
  50
  51 void sem_terminate(SEMAPHORE id);
  52
  53 /*
  54  * sem_grab attempts to gain exclusive access to the given semaphore. If
  55  * it can't get it, the caller will block. Returns -1 on error.
  56  */
  57
  58 int sem_grab(SEMAPHORE id);
  59
  60 /*
  61  * sem_release releases this process's exclusive control over the given
  62  * semaphore. Returns -1 on error.
  63  */
  64
  65 int sem_release(SEMAPHORE id);
  66
  67
  68 #endif