can you try to get ACE_OS::last_error();
Not all the platforms support suspend.
Which kernel version you have. Most likely your kernel doesn't support suspend.
BTW, suspend from another thread is not good idea.
My kernel is 2.6.17-10 ...
I tried ACE_OS::last_error(), which returned 95.
I used ACE_OS::perror, it said "Operation not supported"
I got it, thanks very much
One more thing, "suspend from another thread is not good idea", do you mean such action may cause fatal error like segment fault , or mean it may suspend that thread in some unexpected place?