cpython/Python/thread_os2.h

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
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permission.

While CWI is the initial source for this software, a modified version
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(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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******************************************************************/

/* This code implemented by cvale@netcom.com */

#define INCL_DOSPROCESS
#define INCL_DOSSEMAPHORES
#include "os2.h"
#include "limits.h"

#include "process.h"

long get_thread_ident(void);


/*
 * Initialization of the C package, should not be needed.
 */
static void _init_thread(void)
{
}

/*
 * Thread support.
 */
int start_new_thread(void (*func)(void *), void *arg)
{
  int aThread;
  int success = 1;

  aThread = _beginthread(func,4096,arg);

  if( aThread == -1 ) {
    success = 0;
    fprintf(stderr,"aThread failed == %d",aThread);
    dprintf(("_beginthread failed. return %ld\n", errno));
  }

  return success;
}

long get_thread_ident(void)
{
  PPIB pib;
  PTIB tib;

  if (!initialized)
    init_thread();
        
  DosGetInfoBlocks(&tib,&pib);
  return tib->tib_ptib2->tib2_ultid;
}

static void do_exit_thread(int no_cleanup)
{
  dprintf(("%ld: exit_thread called\n", get_thread_ident()));
  if (!initialized)
    if (no_cleanup)
      _exit(0);
    else
      exit(0);
  _endthread();
}

void exit_thread(void)
{
  do_exit_thread(0);
}

void _exit_thread(void)
{
  do_exit_thread(1);
}

#ifndef NO_EXIT_PROG
static void do_exit_prog(int status, int no_cleanup)
{
  dprintf(("exit_prog(%d) called\n", status));
  if (!initialized)
    if (no_cleanup)
      _exit(status);
    else
      exit(status);
}

void exit_prog(int status)
{
  do_exit_prog(status, 0);
}

void _exit_prog _P1(int status)
{
  do_exit_prog(status, 1);
}
#endif /* NO_EXIT_PROG */

/*
 * Lock support. It has too be implemented as semaphores.
 * I [Dag] tried to implement it with mutex but I could find a way to
 * tell whether a thread already own the lock or not.
 */
type_lock allocate_lock(void)
{
  HMTX   aLock;
  APIRET rc;

  dprintf(("allocate_lock called\n"));
  if (!initialized)
    init_thread();

  DosCreateMutexSem(NULL,  /* Sem name      */
                    &aLock, /* the semaphone */
                    0,     /* shared ?      */
                    0);    /* initial state */  

  dprintf(("%ld: allocate_lock() -> %lx\n", get_thread_ident(), (long)aLock));

  return (type_lock) aLock;
}

void free_lock(type_lock aLock)
{
  dprintf(("%ld: free_lock(%lx) called\n", get_thread_ident(),(long)aLock));

  DosCloseMutexSem((HMTX)aLock);
}

/*
 * Return 1 on success if the lock was acquired
 *
 * and 0 if the lock was not acquired. This means a 0 is returned
 * if the lock has already been acquired by this thread!
 */
int acquire_lock(type_lock aLock, int waitflag)
{
  int   success = 1;
  ULONG rc, count;
  PID   pid = 0;
  TID   tid = 0;

  dprintf(("%ld: acquire_lock(%lx, %d) called\n", get_thread_ident(),
           (long)aLock, waitflag));

  DosQueryMutexSem((HMTX)aLock,&pid,&tid,&count);
  if( tid == get_thread_ident() ) { /* if we own this lock */
    success = 0;
  } else {
    rc = DosRequestMutexSem((HMTX) aLock,
                            (waitflag == 1 ? SEM_INDEFINITE_WAIT : 0));
    
    if( rc != 0) {
      success = 0;                /* We failed */
    }
  }

  dprintf(("%ld: acquire_lock(%lx, %d) -> %d\n",
           get_thread_ident(),(long)aLock, waitflag, success));

  return success;
}

void release_lock(type_lock aLock)
{
  dprintf(("%ld: release_lock(%lx) called\n", get_thread_ident(),(long)aLock));

  if ( DosReleaseMutexSem( (HMTX) aLock ) != 0 ) {
    dprintf(("%ld: Could not release_lock(%lx) error: %l\n",
             get_thread_ident(), (long)aLock, GetLastError()));
  }
}

/*
 * Semaphore support.
 */
type_sema allocate_sema(int value)
{
  return (type_sema) 0;
}

void free_sema(type_sema aSemaphore)
{

}

void down_sema(type_sema aSemaphore, int waitflag)
{
  return -1;
}

void up_sema(type_sema aSemaphore)
{
  dprintf(("%ld: up_sema(%lx)\n", get_thread_ident(), (long)aSemaphore));
}