is cyrus' sieve thread safe

[Dilyan Palauzov]

   Hello,
   I was not able to find information, if cyrus' sieve is thread safe.  
This means, that if one application calls three times  
sieve_interp_alloc, and then executes for first time  
sieve_interp_free, will it continue functioning correctly with the tho  
other implementations, until their sieve_interp_free is called?
   Thanks in advance for your answer,
     Дилян