Kenji Arai / mbed-os_TYBLE16

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Dependents:   TYBLE16_simple_data_logger TYBLE16_MP3_Air

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Semaphore Class Reference
Public Member Functions | Private Member Functions

Semaphore Class Reference
[Semaphore class]

The Semaphore class is used to manage and protect access to a set of shared resources. More...

#include <Semaphore.h>

Inherits NonCopyable< Semaphore >.

Public Member Functions

 Semaphore (int32_t count=0)
 Create and Initialize a Semaphore object used for managing resources.
 Semaphore (int32_t count, uint16_t max_count)
 Create and Initialize a Semaphore object used for managing resources.
 MBED_DEPRECATED_SINCE ("mbed-os-5.13","Replaced with acquire, try_acquire() and try_acquire_for() functions") int32_t wait(uint32_t millisec
 Wait until a Semaphore resource becomes available.
 MBED_DEPRECATED_SINCE ("mbed-os-5.13","Replaced with try_acquire_until()") int32_t wait_until(uint64_t millisec)
 Wait until a Semaphore resource becomes available.
void acquire ()
 Wait until a Semaphore resource becomes available.
bool try_acquire ()
 Try to acquire a Semaphore resource, and return immediately.
bool try_acquire_for (uint32_t millisec)
 Wait until a Semaphore resource becomes available.
bool try_acquire_until (uint64_t millisec)
 Wait until a Semaphore resource becomes available.
osStatus release (void)
 Release a Semaphore resource that was obtain with Semaphore::acquire.
 ~Semaphore ()
 Semaphore destructor.

Private Member Functions

 MBED_DEPRECATED ("Invalid copy construction of a NonCopyable resource.") NonCopyable(const NonCopyable &)
 NonCopyable copy constructor.
 MBED_DEPRECATED ("Invalid copy assignment of a NonCopyable resource.") NonCopyable &operator
 NonCopyable copy assignment operator.

Detailed Description

The Semaphore class is used to manage and protect access to a set of shared resources.

Note:
Memory considerations: The semaphore control structures will be created on current thread's stack, both for the mbed OS and underlying RTOS objects (static or dynamic RTOS memory pools are not being used).

Definition at line 47 of file Semaphore.h.

Constructor & Destructor Documentation

Semaphore ( int32_t  count = 0 )

Create and Initialize a Semaphore object used for managing resources.

Parameters:
countnumber of available resources; maximum index value is (count-1). (default: 0).
Note:
You cannot call this function from ISR context.

Definition at line 33 of file Semaphore.cpp.

Semaphore ( int32_t  count,
uint16_t  max_count 
)

Create and Initialize a Semaphore object used for managing resources.

Parameters:
countnumber of available resources
max_countmaximum number of available resources
Note:
You cannot call this function from ISR context.

Definition at line 38 of file Semaphore.cpp.

~Semaphore (  )

Semaphore destructor.

Note:
You cannot call this function from ISR context.

Definition at line 220 of file Semaphore.cpp.

Member Function Documentation

void acquire ( void   )

Wait until a Semaphore resource becomes available.

Note:
You cannot call this function from ISR context.

Definition at line 146 of file Semaphore.cpp.

MBED_DEPRECATED_SINCE ( "mbed-os-5.13"  ,
"Replaced with try_acquire_until()"   
)

Wait until a Semaphore resource becomes available.

Parameters:
millisecabsolute timeout time, referenced to Kernel::get_ms_count()
Returns:
number of available tokens, before taking one; or -1 in case of incorrect parameters
Note:
the underlying RTOS may have a limit to the maximum wait time due to internal 32-bit computations, but this is guaranteed to work if the wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded, the acquire attempt will time out earlier than specified.
You cannot call this function from ISR context.
MBED_DEPRECATED_SINCE ( "mbed-os-5.13"  ,
"Replaced with   acquire,
try_acquire() and try_acquire_for() functions"   
)

Wait until a Semaphore resource becomes available.

Parameters:
millisectimeout value. (default: osWaitForever).
Returns:
number of available tokens, before taking one; or -1 in case of incorrect parameters
Note:
You may call this function from ISR context if the millisec parameter is set to 0.
osStatus release ( void   )

Release a Semaphore resource that was obtain with Semaphore::acquire.

Returns:
status code that indicates the execution status of the function: osOK the token has been correctly released. osErrorResource the maximum token count has been reached. osErrorParameter internal error.
Note:
You may call this function from ISR context.

Definition at line 204 of file Semaphore.cpp.

bool try_acquire (  )

Try to acquire a Semaphore resource, and return immediately.

Returns:
true if a resource was acquired, false otherwise.
Note:
equivalent to try_acquire_for(0)
You may call this function from ISR context.

Definition at line 70 of file Semaphore.cpp.

bool try_acquire_for ( uint32_t  millisec )

Wait until a Semaphore resource becomes available.

Parameters:
millisectimeout value.
Returns:
true if a resource was acquired, false otherwise.
Note:
You may call this function from ISR context if the millisec parameter is set to 0.

Definition at line 162 of file Semaphore.cpp.

bool try_acquire_until ( uint64_t  millisec )

Wait until a Semaphore resource becomes available.

Parameters:
millisecabsolute timeout time, referenced to Kernel::get_ms_count()
Returns:
true if a resource was acquired, false otherwise.
Note:
the underlying RTOS may have a limit to the maximum wait time due to internal 32-bit computations, but this is guaranteed to work if the wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded, the acquire attempt will time out earlier than specified.
You cannot call this function from ISR context.

Definition at line 184 of file Semaphore.cpp.

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