man > proc_pid_task(5)

proc_pid_task(5)                         File Formats Manual                        proc_pid_task(5)

NAME
       /proc/pid/task/, /proc/tid/, /proc/thread-self/ - thread information

DESCRIPTION
       /proc/pid/task/ (since Linux 2.6.0)
              This  is  a  directory  that contains one subdirectory for each thread in the process.
              The name of each subdirectory is the numerical thread ID (tid) of the thread (see get‐
              tid(2)).

              Within each of these subdirectories, there is a set of files with the same  names  and
              contents  as  under  the /proc/pid directories.  For attributes that are shared by all
              threads, the contents for each of the files under the task/tid subdirectories will  be
              the  same  as  in the corresponding file in the parent /proc/pid directory (e.g., in a
              multithreaded process, all of the task/tid/cwd files will have the same value  as  the
              /proc/pid/cwd  file  in  the  parent  directory, since all of the threads in a process
              share a working directory).  For attributes that are distinct  for  each  thread,  the
              corresponding  files under task/tid may have different values (e.g., various fields in
              each of the task/tid/status files may be different for each thread), or they might not
              exist in /proc/pid at all.

              In a multithreaded process, the contents  of  the  /proc/pid/task  directory  are  not
              available   if   the   main  thread  has  already  terminated  (typically  by  calling
              pthread_exit(3)).

       /proc/tid/
              There  is a numerical subdirectory for each running thread that is not a thread  group
              leader  (i.e., a thread whose thread ID is not the same as its process ID); the subdi‐
              rectory is named by the thread ID.  Each one of these  subdirectories  contains  files
              and  subdirectories exposing information about the thread with the thread ID tid.  The
              contents of these directories are the same as the corresponding /proc/pid/task/tid di‐
              rectories.

              The /proc/tid subdirectories are not visible when iterating through  /proc  with  get‐
              dents(2) (and thus are not visible when one uses ls(1) to view the contents of /proc).
              However,  the pathnames of these directories are visible to (i.e., usable as arguments
              in) system calls that operate on pathnames.

       /proc/thread-self/ (since Linux 3.17)
              This directory refers to the thread accessing the /proc filesystem, and  is  identical
              to  the /proc/self/task/tid directory named by the process thread ID (tid) of the same
              thread.

SEE ALSO
       proc(5)

Linux man-pages 6.7                          2023-08-15                             proc_pid_task(5)