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 nu-
merical 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 directo-
ries. For attributes that are shared by all threads, the con-
tents 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 ter-
minated (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 filesys-
tem, 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)
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