The Mutex class is used to synchronize the execution of threads. More...

#include <Mutex.h>

Inheritance diagram for Mutex:

Public Member Functions
	Mutex ()
	Create and Initialize a Mutex object. More...

	Mutex (const char *name)
	Create and Initialize a Mutex object. More...

osStatus	lock (void)
	Wait until a Mutex becomes available. More...

osStatus	lock (uint32_t millisec)
	Wait until a Mutex becomes available. More...

bool	trylock ()
	Try to lock the mutex, and return immediately. More...

bool	trylock_for (uint32_t millisec)
	Try to lock the mutex for a specified time. More...

bool	trylock_until (uint64_t millisec)
	Try to lock the mutex until specified time. More...

osStatus	unlock ()
	Unlock the mutex that has previously been locked by the same thread. More...

osThreadId	get_owner ()
	Get the owner the this mutex. More...

	~Mutex ()
	Mutex destructor. More...

Detailed Description

The Mutex class is used to synchronize the execution of threads.

This is, for example, used to protect access to a shared resource.

Note: You cannot use member functions of this class in ISR context. If you require Mutex functionality within ISR handler, consider using Semaphore.; Memory considerations: The mutex control structures are created on the 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 66 of file Mutex.h.

Constructor & Destructor Documentation

Mutex ( )

Create and Initialize a Mutex object.

Note: You cannot call this function from ISR context.

Mutex ( const char * name )

Create and Initialize a Mutex object.

Parameters

name	name to be used for this mutex. It has to stay allocated for the lifetime of the thread.

Note: You cannot call this function from ISR context.

~Mutex ( )

Mutex destructor.

Note: You cannot call this function from ISR context.

Member Function Documentation

osThreadId get_owner ( )

Get the owner the this mutex.

Returns: the current owner of this mutex.

Note: You cannot call this function from ISR context.

osStatus lock ( void )

Wait until a Mutex becomes available.

Returns: status code that indicates the execution status of the function: osOK the mutex has been obtained.

Note: You cannot call this function from ISR context.; This function treats RTOS errors as fatal system errors, so it can only return osOK. Use of the return value is deprecated, as the return is expected to become void in the future.

osStatus lock ( uint32_t millisec )

Wait until a Mutex becomes available.

Deprecated:: Do not use this function. This function has been replaced with lock(), trylock() and trylock_for() functions.

Parameters

millisec timeout value.

Returns: status code that indicates the execution status of the function: osOK the mutex has been obtained. osErrorTimeout the mutex could not be obtained in the given time. osErrorResource the mutex could not be obtained when no timeout was specified.

Note: You cannot call this function from ISR context.; This function treats RTOS errors as fatal system errors, so it can only return osOK or osErrorResource in case when millisec is 0 or osErrorTimeout if millisec is not osWaitForever.

bool trylock ( )

Try to lock the mutex, and return immediately.

Returns: true if the mutex was acquired, false otherwise.

Note: equivalent to trylock_for(0); You cannot call this function from ISR context.

bool trylock_for ( uint32_t millisec )

Try to lock the mutex for a specified time.

Parameters

millisec timeout value.

Returns: true if the mutex 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 lock attempt will time out earlier than specified.; You cannot call this function from ISR context.

bool trylock_until ( uint64_t millisec )

Try to lock the mutex until specified time.

Parameters

millisec absolute timeout time, referenced to Kernel::get_ms_count()

Returns: true if the mutex 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 lock attempt will time out earlier than specified.; You cannot call this function from ISR context.

osStatus unlock ( )

Unlock the mutex that has previously been locked by the same thread.

Returns: status code that indicates the execution status of the function: osOK the mutex has been released.

Note: You cannot call this function from ISR context.; This function treats RTOS errors as fatal system errors, so it can only return osOK. Use of the return value is deprecated, as the return is expected to become void in the future.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

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