Trouble when mixing POSIX and Classic API

[Alexander I. Shaykhrazeev]

Greetings,
May somebody help me solve problem with mixed API's usage: Classic and 
POSIX?
I had witten small TCP multiclient server based on POSIX threads for 
controlling resource. When one client connected and writing to resource it's
locked and may be freed by current owner. But if owner is shel, it's 
works incorrect. Any network client may intercept exclusive write access 
from this thread.
When I had analysed this behavior, I had found strange thing: shel 
thread couldn't be found by POSIX routine "pthread_getschedparam" and 
returns ESRCH.
It's means that owner of the lock is dead and new thread (client) may 
lock exclusive write mode. But owner thread is alive.
This is not happen when owner is a POSIX thread.

Is it normal behavior? If so, I solve this another.

-- 
Alexander I. Shaykhrazeev
Morion Inc.