[Libusb-devel] sync API is not thread safe?

[Ludovic R. <lud...@gm...>]

Hello,

I have a problem with my code and I discovered I can reproduce it
using only the synchronous API.

I use two threads.
thread A is calling libusb_interrupt_transfer()
thread B is calling libusb_bulk_transfer() for write and read in a endless loop

Some times the loop is suspended for 1 minute and then continues.
The suspend duration is the duration used in libusb_handle_events()
from io.c. If I change the 60s timeout in libusb_handle_events() to 6s
timeout my loop is halted for 6s instead of 60s.
The loop also continues if the libusb_interrupt_transfer() returns
(after an event occurs on my device).

It seems the code used in do_sync_bulk_transfer() is not correct if
used from two threads at the same time.
I use the same context (NULL= default) and the same device (but on two
different endpoints) in the two threads.

I was wondering why the code in do_sync_bulk_transfer() is so much
simpler than the code given in example in "Multi-threaded applications
and asynchronous I/O " [1].

[1] also says "libusb is a thread-safe library, but extra
considerations must be applied to applications which interact with
libusb from multiple threads."
And my application uses multiple threads.

What should I do?

Thanks

[1] http://libusb.sourceforge.net/api-1.0/mtasync.html

-- 
 Dr. Ludovic Rousseau