Can PySerial's write method be called by multiple threads?

[Joel Koltner]

I have a multi-threaded application where several of the threads need to write 
to a serial port that's being handled by pySerial.  If pySerial thread-safe in 
the sense that pySerial.write behaves atomically?  I.e., if thread 1 executes, 
serport.write("Hello, world!") and thread 2 executes serport.write("All your 
bases are belong to us!"), is it guaranteed that the output over the serial 
port won't "mix" the two together (e.g., "Hello All your bases are belong to 
us!, world!") ?

I looked at the source code, and the write method eventually boils down to 
calling an the OS's "write" function, which presumably ends up being a call to 
a C function.  Given the global interpreter lock -- and particularly how C 
functions can't be interrupted by the Python interpreter at all -- it sure 
seems as though everything is copacetic here?

If not I can just add a queue and have everything go through it, but of course 
I'd like to avoid the extra code and CPU cycles if it isn't at all necessary.

Thank you,
---Joel Koltner