PTHREAD...TPSHARED(3POSIX)

✨ PROLOG ✨

ok so bestie, quick heads up before we dive in 💖 this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so pls go check the corresponding Linux manual page for the deets on Linux behavior), or honestly the interface might not even be implemented on Linux at all. 🙈

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🎀 NAME 🎀

pthread_condattr_getpshared, pthread_condattr_setpshared — get and set the process-shared condition variable attributes 💅

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🌸 SYNOPSIS 🌸

#include <pthread.h>

int pthread_condattr_getpshared(const pthread_condattr_t *restrict attr,
    int *restrict pshared);
int pthread_condattr_setpshared(pthread_condattr_t *attr,
    int pshared);

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🦋 DESCRIPTION 🦋

ok so here's the tea ☕

pthread_condattr_getpshared() shall obtain the value of the process-shared attribute from the attributes object referenced by attr. It's giving "read the vibe, report back". 👑

pthread_condattr_setpshared() shall set the process-shared attribute in an initialized attributes object referenced by attr. It's giving "change the vibe, respectfully". ✨

So what even is the process-shared attribute?? Bestie. Set it to PTHREAD_PROCESS_SHARED and you're basically saying: this condition variable can be operated upon by any thread that has access to the memory where the condition variable is allocated — even if that memory is shared by multiple processes. iconic behavior fr fr. See Section 2.9.9, Synchronization Object Copies and Alternative Mappings for further requirements (iykyk).

The default value of the attribute is PTHREAD_PROCESS_PRIVATE. 🏠

⚠️ lowkey important: the behavior is undefined if the value specified by the attr argument to pthread_condattr_getpshared() or pthread_condattr_setpshared() does not refer to an initialized condition variable attributes object. not me being dramatic, that's literally what it says. 💀

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⭐ RETURN VALUE ⭐

If successful, the pthread_condattr_setpshared() function shall return zero 🫶 — otherwise, an error number shall be returned to indicate the error.

If successful, the pthread_condattr_getpshared() function shall return zero and store the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Otherwise, an error number shall be returned to indicate the error. 💖

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💜 ERRORS 💜

The pthread_condattr_setpshared() function may fail if:

• EINVAL — the new value specified for the attribute is outside the range of legal values for that attribute. bestie that value is Not Invited. 🚫

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

The following sections are informative. (translation: the juicy lore, not the actual spec, but still slay) 🍓

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🌈 EXAMPLES 🌈

None. — yeah. nothing here. not a single one. moving on. 🧚

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🎀 APPLICATION USAGE 🎀

None. — again, nothing. the void. 💀

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🔥 RATIONALE 🔥

If an implementation detects that the value specified by the attr argument to pthread_condattr_getpshared() or pthread_condattr_setpshared() does not refer to an initialized condition variable attributes object, it is recommended that the function should fail and report an [EINVAL] error. like, that's the polite thing to do honestly. 🙈

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👑 FUTURE DIRECTIONS 👑

None. — she's stable, she's not going anywhere, main character energy forever. ✨

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💖 SEE ALSO 💖

• pthread_create()
• pthread_cond_destroy()
• pthread_condattr_destroy()
• pthread_mutex_destroy()

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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ok bye bestie, that's the whole page!! 💅 this one came from IEEE/The Open Group, 2017 — the PTHREAD...TPSHARED(3POSIX) of it all. go forth and share your process-shared condition variables responsibly. 🦋✨💖