OS_LockMutexFrom[RToW|WToR]

Syntax

#include <nitro/os.h>

void OS_LockMutexFromRToW( OSMutex* mutex );

void OS_LockMutexFromWToR( OSMutex* mutex );

Arguments

mutex Pointer to the OSMutex structure

Return Values

None.

Description

Changes the type of the mutex that is locked.

mutex is the pointer to the OSMutex structure to be changed.

The OS_LockMutexFromWToR function takes a mutex that is set to write lock and changes the setting to read lock. The mutex type is then read lock. To unlock it you need to execute either the OS_UnlockMutexR or OS_UnlockMutexRW function.

The OS_LockMutexFromRToW takes a mutex that is set to read lock and changes the setting to write lock. The mutex type is then write lock. To unlock it you need to execute either the OS_UnlockMutexW or OS_UnlockMutexRW function.

Control will not return from either of these functions until the change has succeeded. Internally, the OS_TryLockMutexFromWToR and OS_TryLockMutexFromRToW functions will be called repeatedly until the process succeeds. The process will stop, however, if the function has been specified in a way that cannot succeed. For example, if the OS_LockMutexFromToWToR function is called to change the mutex from write lock to read lock but the mutex is already set to read lock. (The thread goes to sleep.)

Revision History

2008/12/17 Initial version.