I found syscall kill() can send signal to a thread id, which is not the TGID. But the Linux manual page kill(2) said: "The kill() system call can be used to send any signal to any process group or process." And the Linux manual page tkill(2) said: "tgkill() sends the signal sig to the thread with the thread ID tid in the thread group tgid. (By contrast, kill(2) can be used to send a signal only to a process (i.e., thread group) as a whole, and the signal will be delivered to an arbitrary thread within that process.)" I don't know whether the meaning of this 'process' should be the TGID? Because I found kill(tid, 0) will return ESRCH on FreeBSD, while Linux sends signal to the thread group that the thread belongs to. If this is as expected, should we add a notice to the Linux manual page? Because it's a syscall and the pids not equal to tgid are not listed under /proc. This may be a little confusing, I guess. Regards, Cambda
