I am new to Linux programming and my work involves changing an abstraction layer which made Nucleus calls, to Linux calls.

In Case of Events Nucleus has calls like
NU_Set_Events()
NU_Retrieve_Events()

Can I use the POSIX thread conditional variables for Linux?
Can I use the System V calls for events for threads of a same process? Please let me know how I can go about doing it.
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In Case of Pipes Nucleus has calls like
NU_Send_To_Pipe()
NU_Receive_From_Pipe()
NU_Send_To_Front_Of_Pipe()

These calls have a suspend as one parameter by which the pipe can be suspended or can return back immediately if the pipe cannot be written into or read from.
But in Linux, in case of pipes created by pipe() or open() system call, the pipe has only the suspend functionality where in it will suspend till it can read from or write to pipe.

Moreover in Nucleus, NU_Send_To_Front_Of_Pipe() writes to front of the pipe for urgent messages.

How do I implement these functionalities in Linux?

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In case of Mutexes and Semaphores,
The Nucleus has functionalities where the thread can try locking mutexes or acquiring semaphores for a specified amount of time, after which they return back if mutex/semaphore is unavailable.
How can this be implemented in Linux? Can nanosleep() be used here?

Kindly suggest some solutions.
Thanks.

Taklu.