Semaphores
|
semCreate ( ) |
|
| Name: |
semCreate ( ) - creates a semaphore |
| Synopsis: |
SEM_HANDLE semCreate
(
u32 u32InitialCount /* initial count of new semaphore */
)
|
| Description: |
Creates a counting semaphore with an initial count of u32InitialCount.
|
| Include: |
sempaphore.h |
| Returns: |
The SEM_HANDLE of the newly created semaphore. Note that
this function will not return if the semaphore cannot be created,
instead the system will halt (during development) or reboot (if in
the field) so there are no illegal values that can be returned. |
| See Also: |
semDestroy semTake
semGive semGetCount
|
|
semDestroy ( ) |
|
| Name: |
semDestroy ( ) - destroys a semaphore |
| Synopsis: |
void semDestroy
(
SEM_HANDLE semHandle /* semaphore to destroy */
)
|
| Description: |
Deletes a semaphore. Be careful not delete a semaphore while there
are any other threads waiting on it. To do this is undefined behavior.
|
| Include: |
sempaphore.h |
| Returns: |
nothing |
| See Also: |
semCreate |
|
semTake ( ) |
|
| Name: |
semTake ( ) - takes a semaphore |
| Synopsis: |
STATUS semTake
(
SEM_HANDLE semHandle, /* semaphore to take */
u32 u32MillisecondsToWait /* number of milliseconds to wait */
)
|
| Description: |
Takes a semaphore. If the current count is 0, the call blocks for
u32MillisecondsToWait. The u32MillisecondsToWait parameter
may be set to NO_WAIT to make a non blocking request or the
value of WAIT_FOREVER can be used to block forever.
Note that this function will never return an error if WAIT_FOREVER
is the parameter passed to u32MillisecondsToWait so there
is no need to check for error status in that case.
|
| Include: |
sempaphore.h |
| Returns: |
SEM_SUCCESS if the semaphore was successfully taken or SEM_TIMEOUT
if the semaphore was unavailable to be taken in the requested time
period. |
| See Also: |
semGive, semGetCount
|
|
semGive ( ) |
|
| Name: |
semGive ( ) - increments a semaphore count |
| Synopsis: |
void semGive
(
SEM_HANDLE semHandle /* semaphore to increment the count of */
)
|
| Description: |
Increments the count of the given semaphore. |
| Include: |
sempaphore.h |
| Returns: |
nothing |
| See Also: |
semTake, semGetCount
|
|
semGetCount ( ) |
|
| Name: |
semGetCount ( ) - get semaphore count |
| Synopsis: |
u32 semGetCount
(
SEM_HANDLE semHandle /* semaphore to get the count of */
)
|
| Description: |
Returns the current count of the semaphore. |
| Include: |
sempaphore.h |
| Returns: |
The current count of the semaphore. |
| See Also: |
semTake semGive |
|
