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sem.cc

Go to the documentation of this file.

/*
  This software was produced by the National Institute of Standards and
  Technology (NIST), an agency of the U.S. government, and by statute is
  not subject to copyright in the United States.  Recipients of this
  software assume all responsibility associated with its operation,
  modification, maintenance, and subsequent redistribution.
  */

#include "rcs_defs.hh"

extern "C"
{
#ifndef NO_STDIO
#include <stdio.h>              /* NULL */
#endif
#include "_sem.h"
}
#include "sem.hh"
#include "rcs_prnt.hh"          // rcs_print_debug(), PRINT_SEMAPHORE_ACTIVITY
#include "timer.hh"             // etime()


RCS_SEMAPHORE::RCS_SEMAPHORE (unsigned long int _id, int _oflag, double _time,
                              int _mode, int _state)
{
  /* save the constructor args */
  id = _id;
  oflag = _oflag;
  mode = _mode;
  state = _state;
  timeout = _time;

  if (oflag & RCS_SEMAPHORE_CREATE)
    {
      sem = rcs_sem_create (id, mode, state);
    }
  else
    {
      sem = rcs_sem_open ((char *) id, 0);
    }

  if (sem == NULL)
    {
      rcs_print_error
        ("can't create semaphore (id = %d, oflag = %d, timeout = %f, mode = 0x%X, state = %d)\n",
         id, oflag, timeout, mode, state);
    }
}

int
RCS_SEMAPHORE::valid ()
{
  return (sem != NULL);
}

RCS_SEMAPHORE::~RCS_SEMAPHORE ()
{
  if (sem == NULL)
    return;

  /* need to destroy the semaphore before closing our copy */
  if (oflag & RCS_SEMAPHORE_CREATE)
    {

#ifdef LYNX
      char filename[32];
      sprintf (filename, "/tmp/sem%d", id);
      unlink (filename);
#else
      rcs_sem_destroy (sem);
#endif
    }
  rcs_sem_close (sem);
  sem = NULL;
}

int
RCS_SEMAPHORE::wait ()
{
  int retval;
#ifdef DEBUG
  rcs_print_debug (PRINT_SEMAPHORE_ACTIVITY,
                   "semaphore wait started  at %lf\n", etime ());
#endif
  if (sem == NULL)
    return -1;
  retval = rcs_sem_wait (sem, timeout);
#ifdef DEBUG
  rcs_print_debug (PRINT_SEMAPHORE_ACTIVITY,
                   "semaphore wait finished  at %lf\n", etime ());
#endif
  return retval;
}

int
RCS_SEMAPHORE::trywait ()
{
  if (sem == NULL)
    return -1;
  return rcs_sem_trywait (sem);
}

int
RCS_SEMAPHORE::post ()
{
#ifdef DEBUG
  rcs_print_debug (PRINT_SEMAPHORE_ACTIVITY, "semaphore posted at %lf\n",
                   etime ());
#endif
  if (sem == NULL)
    return -1;
  return rcs_sem_post (sem);
}

int
RCS_SEMAPHORE::flush ()
{
#ifdef DEBUG
  rcs_print_debug (PRINT_SEMAPHORE_ACTIVITY, "semaphore flushed at %lf\n",
                   etime ());
#endif
  if (sem == NULL)
    return -1;
  return rcs_sem_flush (sem);
}

int
RCS_SEMAPHORE::getvalue ()
{
  if (sem == NULL)
    return -1;
  return rcs_sem_getvalue (sem, &sval);
}

int
RCS_SEMAPHORE::setflag (int _oflag)
{
  oflag = _oflag;               /* we can reset whether this was the
                                   one who created the semaphore */
  return (0);
}

int
RCS_SEMAPHORE::clear ()
{
  return rcs_sem_clear (sem);
}




// This constructor declared private to prevent copying.
RCS_SEMAPHORE::RCS_SEMAPHORE (RCS_SEMAPHORE & sem)
{
}

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