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 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 direc-
tory (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 termi-
nated (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 path-
names of these directories are visible to (i.e., usable as argu-
ments 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 6.9.1 2024-05-02 proc_pid_task(5)
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