returns the caller's thread ID (TID).
In a single-threaded process, the thread ID
is equal to the process ID (PID, as returned by
In a multithreaded process, all threads
have the same PID, but each one has a unique TID.
For further details, see the discussion of
On success, returns the thread ID of the calling process.
This call is always successful.
system call first appeared on Linux in kernel 2.4.11.
is Linux-specific and should not be used in programs that
are intended to be portable.
Glibc does not provide a wrapper for this system call; call it using
The thread ID returned by this call is not the same thing as a
POSIX thread ID (i.e., the opaque value returned by