Mutex services

Collaboration diagram for Mutex services:

Functions
void	rtdm_mutex_init (rtdm_mutex_t *mutex)
	Initialise a mutex More...
void	rtdm_mutex_destroy (rtdm_mutex_t *mutex)
	Destroy a mutex More...
void	rtdm_mutex_unlock (rtdm_mutex_t *mutex)
	Release a mutex More...
int	rtdm_mutex_lock (rtdm_mutex_t *mutex)
	Request a mutex More...
int	rtdm_mutex_timedlock (rtdm_mutex_t *mutex, nanosecs_rel_t timeout, rtdm_toseq_t *timeout_seq)
	Request a mutex with timeout More...

Detailed Description

Function Documentation

rtdm_mutex_destroy()

void rtdm_mutex_destroy

(

rtdm_mutex_t *

mutex

)

Destroy a mutex

Parameters

[in,out]

mutex

Mutex handle as returned by rtdm_mutex_init()

Tags

task-unrestricted, might-switch

rtdm_mutex_init()

void rtdm_mutex_init

(

rtdm_mutex_t *

mutex

)

Initialise a mutex

This function initalises a basic mutex with priority inversion protection. "Basic", as it does not allow a mutex owner to recursively lock the same mutex again.

Parameters

[in,out]

mutex

Mutex handle

Tags

task-unrestricted

rtdm_mutex_lock()

int rtdm_mutex_lock

(

rtdm_mutex_t *

mutex

)

Request a mutex

This is the light-weight version of rtdm_mutex_timedlock(), implying an infinite timeout.

Parameters

[in,out]

mutex

Mutex handle as returned by rtdm_mutex_init()

Returns

0 on success, otherwise:

• -EIDRM is returned if mutex has been destroyed.
• -EPERM may be returned if an illegal invocation environment is detected.

Tags

primary-only, might-switch

rtdm_mutex_timedlock()

int rtdm_mutex_timedlock	(	rtdm_mutex_t *	mutex,
		nanosecs_rel_t	timeout,
		rtdm_toseq_t *	timeout_seq
	)

Request a mutex with timeout

This function tries to acquire the given mutex. If it is not available, the caller is blocked unless non-blocking operation was selected.

Parameters

[in,out]	mutex	Mutex handle as returned by rtdm_mutex_init()
[in]	timeout	Relative timeout in nanoseconds, see RTDM_TIMEOUT_xxx for special values
[in,out]	timeout_seq	Handle of a timeout sequence as returned by rtdm_toseq_init() or NULL

Returns

0 on success, otherwise:

• -ETIMEDOUT is returned if the if the request has not been satisfied within the specified amount of time.
• -EWOULDBLOCK is returned if timeout is negative and the semaphore value is currently not positive.
• -EIDRM is returned if mutex has been destroyed.
• -EPERM may be returned if an illegal invocation environment is detected.

Tags

primary-only, might-switch

rtdm_mutex_unlock()

void rtdm_mutex_unlock

(

rtdm_mutex_t *

mutex

)

Release a mutex

This function releases the given mutex, waking up a potential waiter which was blocked upon rtdm_mutex_lock() or rtdm_mutex_timedlock().

Parameters

[in,out]

mutex

Mutex handle as returned by rtdm_mutex_init()

Tags

primary-only, might-switch