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# ACE_Process_Semaphore Class Reference

Wrapper for Dijkstra style general semaphores that work across processes. More...

`#include <Process_Semaphore.h>`

Collaboration diagram for ACE_Process_Semaphore:

[legend]
List of all members.

## Public Methods
| ACE_Process_Semaphore (u_int count=1, const ACE_TCHAR *name=0, void *=0, int max=0x7FFFFFFF)
| Initialize the semaphore, with an initial value of <count> and a maximum value of <max>. More...
| ~ACE_Process_Semaphore (void)
| This method is a no-op, i.e., it doesn't remove the semaphore. More...
int | remove (void)
| Explicitly destroy the semaphore. More...
int | acquire (void)
| Block the thread until the semaphore count becomes greater than 0, then decrement it. More...
int | tryacquire (void)
| Conditionally decrement the semaphore if count is greater than 0 (i.e., won't block). More...
int | release (void)
| Increment the semaphore, potentially unblocking a waiting thread. More...
int | acquire_read (void)
| Acquire semaphore ownership. More...
int | acquire_write (void)
| Acquire semaphore ownership. More...
int | tryacquire_read (void)
| Conditionally acquire semaphore (i.e., won't block). More...
int | tryacquire_write (void)
| Conditionally acquire semaphore (i.e., won't block). More...
int | tryacquire_write_upgrade (void)
| This is only here to make the <ACE_Process_Semaphore> interface consistent with the other synchronization APIs. More...
const ACE_sema_t & | lock (void) const
| Return the underlying lock. More...
void | dump (void) const
| Dump the state of an object. More...
## Public Attributes
| ACE_ALLOC_HOOK_DECLARE
| Declare the dynamic allocation hooks. More...
## Protected Attributes
ACE_Semaphore | lock_

## Detailed Description

Wrapper for Dijkstra style general semaphores that work across processes.

## Constructor & Destructor Documentation

ACE_Process_Semaphore::ACE_Process_Semaphore | ( | u_int | count = 1,
|  | const ACE_TCHAR * | name = 0,
|  | void * | arg = 0,
|  | int | max = 0x7FFFFFFF
| ) |

| Initialize the semaphore, with an initial value of <count> and a maximum value of <max>.

ACE_Process_Semaphore::~ACE_Process_Semaphore | ( | void |  | ) |

| This method is a no-op, i.e., it doesn't remove the semaphore. If you want to remove the semaphore, you must call the <remove> method explicitly.

## Member Function Documentation

int ACE_Process_Semaphore::acquire | ( | void |  | ) |

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

ACE_INLINE int ACE_Process_Semaphore::acquire_read | ( | void |  | ) |

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

ACE_INLINE int ACE_Process_Semaphore::acquire_write | ( | void |  | ) |

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

void ACE_Process_Semaphore::dump | ( | void |  | ) | const

| Dump the state of an object.

const ACE_sema_t& ACE_Process_Semaphore::lock | ( | void |  | ) | const

| Return the underlying lock.

int ACE_Process_Semaphore::release | ( | void |  | ) |

| Increment the semaphore, potentially unblocking a waiting thread.

int ACE_Process_Semaphore::remove | ( | void |  | ) |

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

int ACE_Process_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_Process_Semaphore::tryacquire_read | ( | void |  | ) |

| Conditionally acquire semaphore (i.e., won't block). This calls <tryacquire> and is only here to make the <ACE_Process_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_Process_Semaphore::tryacquire_write | ( | void |  | ) |

| Conditionally acquire semaphore (i.e., won't block). This calls <tryacquire> and is only here to make the <ACE_Process_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_Process_Semaphore::tryacquire_write_upgrade | ( | void |  | ) |

| This is only here to make the <ACE_Process_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_Process_Semaphore::ACE_ALLOC_HOOK_DECLARE

| Declare the dynamic allocation hooks.

ACE_Semaphore ACE_Process_Semaphore::lock_`[protected]`

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

- Process_Semaphore.h
- Process_Semaphore.cpp
- Process_Semaphore.inl