PTHREAD_DETACH(3POSIX)

✨ PTHREAD_DETACH(3POSIX) ✨

okay bestie, so this is a page from the POSIX Programmer's Manual (the 3POSIX one, not the Linux one, iykyk), and it's all about pthread_detach. 💅

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🌸 PROLOG 🌸

so like, real talk first: this manual page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ (so pls go consult the corresponding Linux manual page for the deets on Linux behavior), or honestly the interface may not be implemented on Linux at all. no cap. 🙈

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💖 NAME 💖

pthread_detach — detach a thread. that's it. that's the whole vibe. 🦋

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🎀 SYNOPSIS 🎀

#include <pthread.h>

int pthread_detach(pthread_t thread);

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🌈 DESCRIPTION 🌈

okay so pthread_detach() is basically you telling the implementation: "hey bestie, the storage for the thread thread can be reclaimed whenever that thread terminates." 💀✨

and important: if thread hasn't terminated yet, pthread_detach() shall not cause it to terminate. it's not a killer, it's just a note that says "you can clean up after this one." 🫶

⚠️ the behavior is undefined if the value you pass as the thread argument to pthread_detach() does not refer to a joinable thread. like, undefined undefined. don't do it. 🚨

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⭐ RETURN VALUE ⭐

if the call slays (succeeds), pthread_detach() shall return 0. 💚 otherwise, an error number shall be returned to indicate the error. periodt.

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💅 ERRORS 💅

the pthread_detach() function shall not return an error code of [EINTR]. nope, not happening, not on the menu. 🚫

the following sections are informative (aka the bonus lore). 👑

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🍓 EXAMPLES 🍓

None. — literally nothing here bestie, moving on. 🙈

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🧚 APPLICATION USAGE 🧚

None. — also empty. iconic of them tbh. ✨

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👑 RATIONALE 👑

okay so here's the tea ☕:

the pthread_join() or pthread_detach() functions should eventually be called for every thread that is created, so that the storage associated with the thread may be reclaimed. like, that's just the responsible thing. 🫶

people have suggested that a "detach" function isn't even necessary — because the detachstate thread creation attribute is sufficient, since a thread need never be dynamically detached. but bestie, need arises in at least two cases:

1. in a cancellation handler for a pthread_join(), it is nearly essential to have a pthread_detach() function in order to detach the thread on which pthread_join() was waiting. without it, you'd have to make the handler do another pthread_join() to attempt to detach the thread — which would both delay the cancellation processing for an unbounded period and introduce a new call to pthread_join(), which might itself need a cancellation handler. a dynamic detach is nearly essential in this case. 😭
2. in order to detach the "initial thread" (as may be desirable in processes that set up server threads). 💅

if an implementation detects that the value specified by the thread argument to pthread_detach() does not refer to a joinable thread, it is recommended that the function should fail and report an [EINVAL] error.

if an implementation detects use of a thread ID after the end of its lifetime, it is recommended that the function should fail and report an [ESRCH] error. 👀

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🦋 FUTURE DIRECTIONS 🦋

None. — the future is empty, live in the now. 🌸

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🔥 SEE ALSO 🔥

• pthread_join()

the Base Definitions volume of POSIX.1‐2017, <pthread.h> — go read it, bestie. 📚

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💜 COPYRIGHT 💜

portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. in the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. the original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. to report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . 🙈

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and that's the whole page, bestie! 🎀 brought to you by IEEE/The Open Group, dated 2017, under the PTHREAD_DETACH(3POSIX) name — go forth and detach responsibly, ily 💖✨