Mutex and posix

[Luca Pascali <pasckosky2000@yahoo.it>]

Just a little question, my curiosity about the thread module.

I found in Posix (this is from 'info libc' page on section Mutexes) 
these three functions

Function: int pthread_mutex_lock (pthread_mutex_t *mutex))
Function: int pthread_mutex_trylock (pthread_mutex_t *MUTEX)
Function: int pthread_mutex_timedlock (pthread_mutex_t *MUTEX, const 
struct timespec *ABSTIME)

1) for waiting indefinetly for a mutex,
2) failing immediatly if a mutex is locked,
3) wait for a specified amount of time and failing if mutex is still 
locked when time is expired

Module Mutex, provides an interface only to the first two functions: 
lock and try_lock.

My question is:
is there any reason for this situation?

Polling continously is different. If I have two threads that are running 
with scantimes one multiple of the other, it is possible that one of the 
two threads (the slower one) fails always or almost always the try_lock 
command.

Luca

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Luca Pascali
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