PTHREAD_B...ER_DESTROY(3P)

💖 PTHREAD_BARRIER_DESTROY(3P) 💖

okay bestie, welcome to the POSIX Programmer's Manual page for pthread_barrier_destroy, pthread_barrier_init — destroy and initialize a barrier object. yes we're doing barriers today and yes it's iconic 💅

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🌸 PROLOG 🌸

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

no cap, read that twice. POSIX says one thing, your Linux box might do another thing, and sometimes the thing doesn't even exist on Linux at all. vibe check your platform first 🫶

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✨ NAME ✨

pthread_barrier_destroy, pthread_barrier_init — destroy and initialize a barrier object

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🎀 SYNOPSIS 🎀

#include <pthread.h>

int pthread_barrier_destroy(pthread_barrier_t *barrier);
int pthread_barrier_init(pthread_barrier_t *restrict barrier,
    const pthread_barrierattr_t *restrict attr, unsigned count);

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💜 DESCRIPTION 💜

so pthread_barrier_destroy() shall destroy the barrier referenced by barrier and release any resources used by the barrier. after that, the effect of subsequent use of the barrier is undefined until the barrier is reinitialized by another call to pthread_barrier_init(). an implementation may use this function to set barrier to an invalid value. and the results are undefined if pthread_barrier_destroy() is called when any thread is blocked on the barrier, or if this function is called with an uninitialized barrier. 🫠

pthread_barrier_init() shall allocate any resources required to use the barrier referenced by barrier and shall initialize the barrier with attributes referenced by attr. if attr is NULL, the default barrier attributes shall be used — the effect is the same as passing the address of a default barrier attributes object. the results are undefined if pthread_barrier_init() is called when any thread is blocked on the barrier (that is, has not returned from the pthread_barrier_wait() call). the results are undefined if a barrier is used without first being initialized. and the results are undefined if pthread_barrier_init() is called specifying an already initialized barrier. three whole undefined-behavior situations, we love a chaotic queen 😭

the count argument specifies the number of threads that must call pthread_barrier_wait() before any of them successfully return from the call. the value specified by count must be greater than zero. like, strictly. zero is not it bestie.

if the pthread_barrier_init() function fails, the barrier shall not be initialized and the contents of barrier are undefined.

See Section 2.9.9, Synchronization Object Copies and Alternative Mappings for further requirements. iykyk 📚

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🔥 RETURN VALUE 🔥

upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate the error. (yes, error number, not errno — she returns it directly, main character energy 👑)

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💀 ERRORS 💀

the pthread_barrier_init() function shall fail if:

• EAGAIN — the system lacks the necessary resources to initialize another barrier. 😭
• EINVAL — the value specified by count is equal to zero.
• ENOMEM — insufficient memory exists to initialize the barrier.

these functions shall not return an error code of [EINTR]. periodt.

The following sections are informative.

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🌈 EXAMPLES 🌈

None.

(yeah. nothing. we're on our own here bestie 🧚)

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🦋 APPLICATION USAGE 🦋

None.

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⭐ RATIONALE ⭐

if an implementation detects that the value specified by the barrier argument to pthread_barrier_destroy() does not refer to an initialized barrier object, it is recommended that the function should fail and report an [EINVAL] error.

if an implementation detects that the value specified by the attr argument to pthread_barrier_init() does not refer to an initialized barrier attributes object, it is recommended that the function should fail and report an [EINVAL] error.

if an implementation detects that the value specified by the barrier argument to pthread_barrier_destroy() or pthread_barrier_init() refers to a barrier that is in use (for example, in a pthread_barrier_wait() call) by another thread, or detects that the value specified by the barrier argument to pthread_barrier_init() refers to an already initialized barrier object, it is recommended that the function should fail and report an [EBUSY] error.

note the word "recommended" — these are suggestions to the implementation, not promises to you. don't go building your whole error handling on vibes alone 🫶

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🍓 FUTURE DIRECTIONS 🍓

None.

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🧚 SEE ALSO 🧚

• pthread_barrier_wait()
• The Base Definitions volume of POSIX.1‐2017, <pthread.h>

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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, 2017 — go forth and synchronize your threads responsibly, you absolute legend 💅✨🌸