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GETTID(2) Linux Programmer's Manual 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), getpid(2),  get_robust_list(2),
     ioprio_set(2),   perf_event_open(2),  sched_setaffinity(2),  sched_set-
     param(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/.

Linux 2017-09-15 GETTID(2)