ACE_Semaphore Class Reference

Wrapper for Dijkstra style general semaphores. More...

#include <Semaphore.h>

Inheritance diagram for ACE_Semaphore:

Inheritance graph
[legend]
List of all members.

Public Member Functions

 ACE_Semaphore (unsigned int count=1, int type=USYNC_THREAD, const ACE_TCHAR *name=0, void *=0, int max=0x7fffffff)
 Initialize the semaphore, with initial value of "count".
 ~ACE_Semaphore (void)
 Implicitly destroy the semaphore.
int remove (void)
int acquire (void)
int acquire (ACE_Time_Value &tv)
int acquire (ACE_Time_Value *tv)
int tryacquire (void)
int release (void)
int release (unsigned int release_count)
int acquire_read (void)
int acquire_write (void)
int tryacquire_read (void)
int tryacquire_write (void)
int tryacquire_write_upgrade (void)
void dump (void) const
 Dump the state of an object.
const ACE_sema_t & lock (void) const
 Return the underlying lock.

Public Attributes

 ACE_ALLOC_HOOK_DECLARE
 Declare the dynamic allocation hooks.

Protected Attributes

ACE_sema_t semaphore_
int removed_

Private Member Functions

void operator= (const ACE_Semaphore &)
 ACE_Semaphore (const ACE_Semaphore &)

Detailed Description

Wrapper for Dijkstra style general semaphores.


Constructor & Destructor Documentation

ACE_Semaphore::ACE_Semaphore unsigned int  count = 1,
int  type = USYNC_THREAD,
const ACE_TCHAR name = 0,
void *  = 0,
int  max = 0x7fffffff
 

Initialize the semaphore, with initial value of "count".

ACE_Semaphore::~ACE_Semaphore void   ) 
 

Implicitly destroy the semaphore.

ACE_Semaphore::ACE_Semaphore const ACE_Semaphore  )  [private]
 


Member Function Documentation

ACE_INLINE int ACE_Semaphore::acquire ACE_Time_Value tv  ) 
 

If <tv> == 0 then call <acquire()> directly. Otherwise, Block the thread until the semaphore count becomes greater than 0 (at which point it is decremented) or until <tv> times out (in which case -1 is returned and <errno> == <ETIME>). Note that <*tv> is assumed to be in "absolute" rather than "relative" time. The value of <*tv> is updated upon return to show the actual (absolute) acquisition time.

NOTE: Solaris threads do not support timed semaphores. Therefore, if you're running on Solaris you might want to consider using the ACE POSIX pthreads implementation instead, which can be enabled by compiling ACE with -DACE_HAS_PTHREADS, rather than -DACE_HAS_STHREADS or -DACE_HAS_POSIX_SEM.

ACE_INLINE int ACE_Semaphore::acquire ACE_Time_Value tv  ) 
 

Block the thread until the semaphore count becomes greater than 0 (at which point it is decremented) or until <tv> times out (in which case -1 is returned and <errno> == <ETIME>). Note that <tv> is assumed to be in "absolute" rather than "relative" time. The value of <tv> is updated upon return to show the actual (absolute) acquisition time.

NOTE: Solaris threads do not support timed semaphores. Therefore, if you're running on Solaris you might want to consider using the ACE POSIX pthreads implementation instead, which can be enabled by compiling ACE with -DACE_HAS_PTHREADS, rather than -DACE_HAS_STHREADS or -DACE_HAS_POSIX_SEM.

ACE_INLINE int ACE_Semaphore::acquire void   ) 
 

Block the thread until the semaphore count becomes greater than 0, then decrement it.

ACE_INLINE int ACE_Semaphore::acquire_read void   ) 
 

Acquire semaphore ownership. This calls <acquire> and is only here to make the <ACE_Semaphore> interface consistent with the other synchronization APIs.

ACE_INLINE int ACE_Semaphore::acquire_write void   ) 
 

Acquire semaphore ownership. This calls <acquire> and is only here to make the <ACE_Semaphore> interface consistent with the other synchronization APIs.

void ACE_Semaphore::dump void   )  const
 

Dump the state of an object.

Reimplemented in ACE_Thread_Semaphore.

ACE_INLINE const ACE_sema_t & ACE_Semaphore::lock void   )  const
 

Return the underlying lock.

void ACE_Semaphore::operator= const ACE_Semaphore  )  [private]
 

ACE_INLINE int ACE_Semaphore::release unsigned int  release_count  ) 
 

Increment the semaphore by <release_count>, potentially unblocking waiting threads.

ACE_INLINE int ACE_Semaphore::release void   ) 
 

Increment the semaphore by 1, potentially unblocking a waiting thread.

ACE_INLINE int ACE_Semaphore::remove void   ) 
 

Explicitly destroy the semaphore. Note that only one thread should call this method since it doesn't protect against race conditions.

ACE_INLINE int ACE_Semaphore::tryacquire void   ) 
 

Conditionally decrement the semaphore if count is greater than 0 (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>.

ACE_INLINE int ACE_Semaphore::tryacquire_read void   ) 
 

Conditionally acquire semaphore (i.e., won't block). This calls <tryacquire> and is only here to make the <ACE_Semaphore> interface consistent with the other synchronization APIs. Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>.

ACE_INLINE int ACE_Semaphore::tryacquire_write void   ) 
 

Conditionally acquire semaphore (i.e., won't block). This calls <tryacquire> and is only here to make the <ACE_Semaphore> interface consistent with the other synchronization APIs. Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>.

ACE_INLINE int ACE_Semaphore::tryacquire_write_upgrade void   ) 
 

This is only here to make the <ACE_Semaphore> interface consistent with the other synchronization APIs. Assumes the caller has already acquired the semaphore using one of the above calls, and returns 0 (success) always.


Member Data Documentation

ACE_Semaphore::ACE_ALLOC_HOOK_DECLARE
 

Declare the dynamic allocation hooks.

Reimplemented in ACE_Thread_Semaphore.

int ACE_Semaphore::removed_ [protected]
 

Keeps track of whether <remove> has been called yet to avoid multiple <remove> calls, e.g., explicitly and implicitly in the destructor. This flag isn't protected by a lock, so make sure that you don't have multiple threads simultaneously calling <remove> on the same object, which is a bad idea anyway...

ACE_sema_t ACE_Semaphore::semaphore_ [protected]
 


The documentation for this class was generated from the following files:
Generated on Wed Nov 23 15:50:23 2005 for ACE by  doxygen 1.4.5