This is a simple semaphore package that assumes there are no race conditions for initialization (i.e., the order of process startup must be well defined). More...

#include <SV_Semaphore_Simple.h>

Inheritance diagram for ACE_SV_Semaphore_Simple:

[legend]

List of all members.

Public Types
enum	{ ACE_CREATE = IPC_CREAT, ACE_EXCL = IPC_EXCL, ACE_OPEN = 0 }
Public Member Functions
	ACE_SV_Semaphore_Simple (void)
	ACE_SV_Semaphore_Simple (key_t key, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS)
	ACE_SV_Semaphore_Simple (const char *name, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS)
	~ACE_SV_Semaphore_Simple (void)
int	open (const char *name, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS)
int	open (key_t key, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS)
int	close (void)
int	remove (void) const
int	acquire (u_short n=0, short flags=0) const
int	acquire_read (u_short n=0, short flags=0) const
	Acquire a semaphore for reading.
int	acquire_write (u_short n=0, short flags=0) const
	Acquire a semaphore for writing.
int	tryacquire (u_short n=0, short flags=0) const
	Non-blocking version of <acquire>.
int	tryacquire_read (u_short n=0, short flags=0) const
	Try to acquire the semaphore for reading.
int	tryacquire_write (u_short n=0, short flags=0) const
	Try to acquire the semaphore for writing.
int	release (u_short n=0, short flags=0) const
int	op (short val, u_short semnum=0, short flags=SEM_UNDO) const
int	op (sembuf op_vec[], u_short nsems) const
	General ACE_SV_Semaphore operation on an array of SV_Semaphores.
int	control (int cmd, semun arg, u_short n=0) const
int	control (int cmd, int value=0, u_short n=0) const
int	get_id (void) const
	Get underlying internal id.
void	dump (void) const
	Dump the state of an object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Member Functions
int	init (key_t k=static_cast< key_t >(ACE_INVALID_SEM_KEY), int i=-1)
key_t	name_2_key (const char *name)
Protected Attributes
key_t	key_
	Semaphore key.
int	internal_id_
	Internal ID to identify the semaphore group within this process.
int	sem_number_
	Number of semaphores we're creating.

Detailed Description

This is a simple semaphore package that assumes there are no race conditions for initialization (i.e., the order of process startup must be well defined).

Definition at line 50 of file SV_Semaphore_Simple.h.

Member Enumeration Documentation

anonymous enum

Enumerator:

ACE_CREATE
ACE_EXCL
ACE_OPEN

Definition at line 53 of file SV_Semaphore_Simple.h.

  {
    ACE_CREATE = IPC_CREAT,
    ACE_EXCL = IPC_EXCL,
    ACE_OPEN = 0
  };

Constructor & Destructor Documentation

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple ( void )

Definition at line 216 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  this->init ();
}

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple	(	key_t	key,
		short	flags = `ACE_SV_Semaphore_Simple::ACE_CREATE`,
		int	initial_value = `1`,
		u_short	nsems = `1`,
		mode_t	perms = `ACE_DEFAULT_FILE_PERMS`
	)

Definition at line 108 of file SV_Semaphore_Simple.cpp.

  : key_ (k)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  if (this->open (k, flags, initial_value, n, perms) == -1)
    ACE_ERROR ((LM_ERROR,  ACE_TEXT ("%p\n"),  ACE_TEXT ("ACE_SV_Semaphore::ACE_SV_Semaphore")));
}

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple	(	const char *	name,
		short	flags = `ACE_SV_Semaphore_Simple::ACE_CREATE`,
		int	initial_value = `1`,
		u_short	nsems = `1`,
		mode_t	perms = `ACE_DEFAULT_FILE_PERMS`
	)

Definition at line 174 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  if (this->open (name,
                  flags,
                  initial_value,
                  n,
                  perms) == -1)
    ACE_ERROR ((LM_ERROR,
                ACE_TEXT ("%p\n"),
                ACE_TEXT ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple")));
}

ACE_SV_Semaphore_Simple::~ACE_SV_Semaphore_Simple ( void )

Definition at line 210 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::~ACE_SV_Semaphore_Simple");
  this->close ();
}

Member Function Documentation

int ACE_SV_Semaphore_Simple::acquire	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Wait until a ACE_SV_Semaphore's value is greater than 0, the decrement it by 1 and return. Dijkstra's P operation, Tannenbaums DOWN operation.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 64 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::acquire");
  return this->op (-1, n, flags);
}

int ACE_SV_Semaphore_Simple::acquire_read	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Acquire a semaphore for reading.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 71 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::acquire_read");
  return this->acquire (n, flags);
}

int ACE_SV_Semaphore_Simple::acquire_write	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Acquire a semaphore for writing.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 78 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::acquire_write");
  return this->acquire (n, flags);
}

int ACE_SV_Semaphore_Simple::close ( void )

Close a ACE_SV_Semaphore, marking it as invalid for subsequent operations...

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 43 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::close");
  return this->init ();
}

int ACE_SV_Semaphore_Simple::control	(	int	cmd,
		semun	arg,
		u_short	n = `0`
	)			const

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 30 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::control");
  return this->internal_id_ == -1 ?
    -1 : ACE_OS::semctl (this->internal_id_, n, cmd, arg);
}

int ACE_SV_Semaphore_Simple::control	(	int	cmd,
		int	value = `0`,
		u_short	n = `0`
	)			const

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 27 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::control");
  if (this->internal_id_ == -1)
    return -1;
  else
    {
      semun semctl_arg;

      semctl_arg.val = value;
      return ACE_OS::semctl (this->internal_id_,
                             semnum,
                             cmd,
                             semctl_arg);
    }
}

void ACE_SV_Semaphore_Simple::dump ( void ) const

Dump the state of an object.

Reimplemented in ACE_SV_Semaphore_Complex.

int ACE_SV_Semaphore_Simple::get_id ( void ) const

Get underlying internal id.

Definition at line 122 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::get_id");
  return this->internal_id_;
}

int ACE_SV_Semaphore_Simple::init	(	key_t	k = `static_cast<key_t> (ACE_INVALID_SEM_KEY)`,
		int	i = `-1`
	)			`[protected]`

Convert name to key This function is used internally to create keys for the semaphores. A valid name contains letters and digits only and MUST start with a letter.

The method for generating names is not very sophisticated, so caller should not pass strings which match each other for the first LUSED characters when he wants to get a different key.

Definition at line 47 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::init");
  this->key_ = k;
  this->internal_id_ = i;
  return 0;
}

key_t ACE_SV_Semaphore_Simple::name_2_key ( const char * name ) [protected]

Definition at line 128 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::name_2_key");

  if (name == 0)
    {
      errno = EINVAL;
      return static_cast<key_t> (ACE_INVALID_SEM_KEY);
    }

  // Basically "hash" the values in the <name>.  This won't
  // necessarily guarantee uniqueness of all keys.
  // But (IMHO) CRC32 is good enough for most purposes (Carlos)
#if defined (ACE_WIN32) && defined (_MSC_VER)
  // The cast below is legit...
#  pragma warning(push)
#  pragma warning(disable : 4312)
#endif /* defined (ACE_WIN32) && defined (_MSC_VER) */
  return (key_t) ACE::crc32 (name);
#if defined (ACE_WIN32) && defined (_MSC_VER)
#  pragma warning(pop)
#endif /* defined (ACE_WIN32) && defined (_MSC_VER) */
}

int ACE_SV_Semaphore_Simple::op	(	sembuf	op_vec[],
		u_short	nsems
	)			const

General ACE_SV_Semaphore operation on an array of SV_Semaphores.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 52 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::op");
  return this->internal_id_ == -1
    ? -1 : ACE_OS::semop (this->internal_id_, op_vec, n);
}

int ACE_SV_Semaphore_Simple::op	(	short	val,
		u_short	semnum = `0`,
		short	flags = `SEM_UNDO`
	)			const

General ACE_SV_Semaphore operation. Increment or decrement by a specific amount (positive or negative; amount can`t be zero).

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 59 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::op");
  sembuf op_op;

  op_op.sem_num = n;
  op_op.sem_flg = flags;

  if (this->internal_id_ == -1)
    return -1;
  else if ((op_op.sem_op = val) == 0)
    return -1;
  else
    return ACE_OS::semop (this->internal_id_, &op_op, 1);
}

int ACE_SV_Semaphore_Simple::open	(	const char *	name,
		short	flags = `ACE_SV_Semaphore_Simple::ACE_CREATE`,
		int	initial_value = `1`,
		u_short	nsems = `1`,
		mode_t	perms = `ACE_DEFAULT_FILE_PERMS`
	)

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 156 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::open");

  key_t key;

  if (name == 0)
    key = ACE_DEFAULT_SEM_KEY;
  else
    key = this->name_2_key (name);

  return this->open (key, flags, initial_value, n, perms);
}

int ACE_SV_Semaphore_Simple::open	(	key_t	key,
		short	flags = `ACE_SV_Semaphore_Simple::ACE_CREATE`,
		int	initial_value = `1`,
		u_short	nsems = `1`,
		mode_t	perms = `ACE_DEFAULT_FILE_PERMS`
	)

Open or create one or more SV_Semaphores. We return 0 if all is OK, else -1.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 79 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::open");
  union semun ivalue;

  if (k == IPC_PRIVATE || k == static_cast<key_t> (ACE_INVALID_SEM_KEY))
    return -1;

  ivalue.val = initial_value;
  this->key_ = k;
  this->sem_number_ = n;

  this->internal_id_ = ACE_OS::semget (this->key_, n, perms | flags);

  if (this->internal_id_ == -1)
    return -1;

  if (ACE_BIT_ENABLED (flags, IPC_CREAT))
    for (int i = 0; i < n; i++)
      if (ACE_OS::semctl (this->internal_id_, i, SETVAL, ivalue) == -1)
        return -1;

  return 0;
}

int ACE_SV_Semaphore_Simple::release	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Increment ACE_SV_Semaphore by one. Dijkstra's V operation, Tannenbaums UP operation.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 115 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::release");
  return this->op (1, n, flags);
}

int ACE_SV_Semaphore_Simple::remove ( void ) const

Remove all SV_Semaphores associated with a particular key. This call is intended to be called from a server, for example, when it is being shut down, as we do an IPC_RMID on the ACE_SV_Semaphore, regardless of whether other processes may be using it or not. Most other processes should use <close> below.

Definition at line 229 of file SV_Semaphore_Simple.cpp.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::remove");
  int const result = this->control (IPC_RMID);
  ((ACE_SV_Semaphore_Simple *) this)->init ();
  return result;
}

int ACE_SV_Semaphore_Simple::tryacquire	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Non-blocking version of <acquire>.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 87 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::tryacquire");
  return this->op (-1, n, flags | IPC_NOWAIT);
}

int ACE_SV_Semaphore_Simple::tryacquire_read	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Try to acquire the semaphore for reading.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 96 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::tryacquire_read");
  return this->tryacquire (n, flags);
}

int ACE_SV_Semaphore_Simple::tryacquire_write	(	u_short	n = `0`,
		short	flags = `0`
	)			const

Try to acquire the semaphore for writing.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 105 of file SV_Semaphore_Simple.inl.

{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::tryacquire_write");
  return this->tryacquire (n, flags);
}

Member Data Documentation

ACE_SV_Semaphore_Simple::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Reimplemented in ACE_SV_Semaphore_Complex.

Definition at line 163 of file SV_Semaphore_Simple.h.

int ACE_SV_Semaphore_Simple::internal_id_ [protected]

Internal ID to identify the semaphore group within this process.

Definition at line 170 of file SV_Semaphore_Simple.h.

key_t ACE_SV_Semaphore_Simple::key_ [protected]

Semaphore key.

Definition at line 167 of file SV_Semaphore_Simple.h.

int ACE_SV_Semaphore_Simple::sem_number_ [protected]

Number of semaphores we're creating.

Definition at line 173 of file SV_Semaphore_Simple.h.

The documentation for this class was generated from the following files:

ACE_SV_Semaphore_Simple Class Reference

Public Types

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation