gettid(2)

NAME

   gettid - get thread identification

SYNOPSIS

   #include <sys/types.h>

   pid_t gettid(void);

   Note: There is no glibc wrapper for this system call; see NOTES.

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 process.

ERRORS

   This call is always successful.

VERSIONS

   The gettid() system call first appeared on Linux in kernel 2.4.11.

CONFORMING TO

   gettid()  is Linux-specific and should not be used in programs that are
   intended to be portable.

NOTES

   Glibc does not provide a wrapper for this system call;  call  it  using
   syscall(2).

   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),
   ioprio_set(2),         perf_event_open(2),        sched_setaffinity(2),
   sched_setparam(2), sched_setscheduler(2), tgkill(2), timer_create(2)

COLOPHON

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   description  of  the project, information about reporting bugs, and the
   latest    version    of    this    page,    can     be     found     at
   https://www.kernel.org/doc/man-pages/.

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