debian man page for gettid

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  dis-
       cussion 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)).

SEE ALSO
       clone(2), fork(2), getpid(2)

COLOPHON
       This  page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2012-07-13								 GETTID(2)