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 gettid(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  subdirectory  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 directories.

              The  /proc/tid  subdirectories  are not visible when iterating through /proc with getdents(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 6.16                               2025-08-29                                   proc_pid_task(5)