RTEMS  5.1
Files | Data Structures | Macros | Functions
Semaphore Handler

Semaphore Handler. More...

Files

file  coresem.h
 Data Associated with the Counting Semaphore Handler.
 
file  coresemimpl.h
 Inlined Routines Associated with the SuperCore Semaphore.
 
file  semaphoreimpl.h
 Semaphore Implementation.
 
file  coresem.c
 Core Semaphore Initialize.
 

Data Structures

struct  CORE_semaphore_Control
 
struct  Sem_Control
 

Macros

#define SEMAPHORE_TQ_OPERATIONS   &_Thread_queue_Operations_priority
 

Functions

void _CORE_semaphore_Initialize (CORE_semaphore_Control *the_semaphore, uint32_t initial_value)
 Initializes the semaphore based on the parameters passed. More...
 
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Acquire_critical (CORE_semaphore_Control *the_semaphore, Thread_queue_Context *queue_context)
 Acquires the semaphore critical. More...
 
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Release (CORE_semaphore_Control *the_semaphore, Thread_queue_Context *queue_context)
 Releases the semaphore. More...
 
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, Thread_queue_Context *queue_context)
 Destroys the semaphore. More...
 
RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Surrender (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, uint32_t maximum_count, Thread_queue_Context *queue_context)
 Surrenders a unit to the semaphore. More...
 
RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count (const CORE_semaphore_Control *the_semaphore)
 Returns the current count associated with the semaphore. More...
 
RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Seize (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, Thread_Control *executing, bool wait, Thread_queue_Context *queue_context)
 Seizes the semaphore. More...
 

Detailed Description

Semaphore Handler.

This handler encapsulates functionality which provides the foundation Semaphore services used in all of the APIs supported by RTEMS.

Function Documentation

◆ _CORE_semaphore_Acquire_critical()

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Acquire_critical ( CORE_semaphore_Control the_semaphore,
Thread_queue_Context queue_context 
)

Acquires the semaphore critical.

This routine acquires the semaphore.

Parameters
[in,out]the_semaphoreThe semaphore to acquire.
queue_contextThe thread queue context.

◆ _CORE_semaphore_Destroy()

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy ( CORE_semaphore_Control the_semaphore,
const Thread_queue_Operations operations,
Thread_queue_Context queue_context 
)

Destroys the semaphore.

This routine destroys the semaphore.

Parameters
[out]the_semaphoreThe semaphore to destroy.
operationsThe thread queue operations.
queue_contextThe thread queue context.

◆ _CORE_semaphore_Get_count()

RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count ( const CORE_semaphore_Control the_semaphore)

Returns the current count associated with the semaphore.

Parameters
the_semaphoreThe semaphore to obtain the count of.
Returns
the current count of this semaphore.

◆ _CORE_semaphore_Initialize()

void _CORE_semaphore_Initialize ( CORE_semaphore_Control the_semaphore,
uint32_t  initial_value 
)

Initializes the semaphore based on the parameters passed.

This package is the implementation of the CORE Semaphore Handler. This core object utilizes standard Dijkstra counting semaphores to provide synchronization and mutual exclusion capabilities.

This routine initializes the semaphore based on the parameters passed.

Parameters
[out]the_semaphoreThe semaphore to initialize.
initial_valueThe initial count of the semaphore.

◆ _CORE_semaphore_Release()

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Release ( CORE_semaphore_Control the_semaphore,
Thread_queue_Context queue_context 
)

Releases the semaphore.

This routine releases the semaphore.

Parameters
[in,out]the_semaphoreThe semaphore to release.
queue_contextThe thread queue context.

◆ _CORE_semaphore_Seize()

RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Seize ( CORE_semaphore_Control the_semaphore,
const Thread_queue_Operations operations,
Thread_Control executing,
bool  wait,
Thread_queue_Context queue_context 
)

Seizes the semaphore.

This routine attempts to receive a unit from the_semaphore. If a unit is available or if the wait flag is false, then the routine returns. Otherwise, the calling task is blocked until a unit becomes available.

Parameters
[in,out]the_semaphoreThe semaphore to obtain.
operationsThe thread queue operations.
executingThe currently executing thread.
waitIndicates whether the calling thread is willing to wait.
queue_contextis a temporary variable used to contain the ISR disable level cookie.
Return values
STATUS_SUCCESSFULThe semaphore was successfully seized.
STATUS_UNSATISFIEDThe semaphore is currently not free and the calling thread not willing to wait.
STATUS_TIMEOUTA timeout occured.

◆ _CORE_semaphore_Surrender()

RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Surrender ( CORE_semaphore_Control the_semaphore,
const Thread_queue_Operations operations,
uint32_t  maximum_count,
Thread_queue_Context queue_context 
)

Surrenders a unit to the semaphore.

This routine frees a unit to the semaphore. If a task was blocked waiting for a unit from this semaphore, then that task will be readied and the unit given to that task. Otherwise, the unit will be returned to the semaphore.

Parameters
[in,out]the_semaphoreis the semaphore to surrender
operationsThe thread queue operations.
maximum_countThe maximum number of units in the semaphore.
queue_contextis a temporary variable used to contain the ISR disable level cookie.
Return values
STATUS_SUCCESSFULThe unit was successfully freed to the semaphore.
STATUS_MAXIMUM_COUNT_EXCEEDEDThe maximum number of units was exceeded.