NAME

       gettid - get thread identification

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #define _GNU_SOURCE
       #include <unistd.h>

       pid_t gettid(void);

DESCRIPTION

       gettid()  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  getpid(2)).   In  a  multithreaded
       process,  all  threads  have  the  same  PID,  but each one has a unique TID.  For further
       details, see the discussion of CLONE_THREAD in clone(2).

RETURN VALUE

       On success, returns the thread ID of the calling thread.

ERRORS

       This call is always successful.

STANDARDS

       Linux.

HISTORY

       Linux 2.4.11, glibc 2.30.

NOTES

       The thread ID returned by this call is not the same thing as a POSIX thread ID (i.e.,  the
       opaque value returned by pthread_self(3)).

       In  a  new  thread group created by a clone(2) call that does not specify the CLONE_THREAD
       flag (or, equivalently, a new process created by fork(2)), the new  process  is  a  thread
       group leader, and its thread group ID (the value returned by getpid(2)) is the same as its
       thread ID (the value returned by gettid()).

SEE ALSO

       capget(2), clone(2),  fcntl(2),  fork(2),  get_robust_list(2),  getpid(2),  ioprio_set(2),
       perf_event_open(2),    sched_setaffinity(2),   sched_setparam(2),   sched_setscheduler(2),
       tgkill(2), timer_create(2)