assert.h(0P)

✨ assert.h — verify program assertion ✨

okay bestie, welcome to the POSIX Programmer's Manual 💅 this little page lives in the POSIX manual, so let's get the housekeeping out of the way first.

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🫶 PROLOG 🫶

so this manual page is part of the POSIX Programmer's Manual. that's the whole vibe. BUT — and this is important, no cap — the Linux implementation of this interface may differ (so pls go consult the corresponding Linux manual page if you wanna know how Linux actually does it), or the interface may not even be implemented on Linux at all. 😭 it's giving "check your own system, bestie."

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👑 NAME 👑

assert.h — verify program assertion. that's it, that's the whole name section. iconic.

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🎀 SYNOPSIS 🎀

#include <assert.h>

that's the whole thing. one include. she's low maintenance. ✨

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💖 DESCRIPTION 💖

okay so here's the tea. ☕ the functionality described on this reference page is aligned with the ISO C standard. if there's any conflict between the requirements described here and the ISO C standard, that conflict is unintentional — nobody's beefing on purpose. this volume of POSIX.1‐2017 defers to the ISO C standard, periodt.

the <assert.h> header shall define the assert() macro. and it refers to the macro NDEBUG, which is not defined in the header (so don't go looking for it in there, she's not home 🏠).

here's the plot twist: if NDEBUG is defined as a macro name before the inclusion of this header, then the assert() macro shall be defined simply as:

#define assert(ignore)((void) 0)

like, it just evaporates into nothing. poof. 💀

otherwise, the macro behaves as described in assert().

the assert() macro shall be redefined according to the current state of NDEBUG each time <assert.h> is included. so every single include is a fresh vibe check on NDEBUG. 🌈

the assert() macro shall be implemented as a macro, not as a function. and if the macro definition is suppressed in order to access an actual function, the behavior is undefined. ⚠️ like, undefined undefined. do not test this. do not pass go.

also: the following sections are informative. 📝 (yes, that's a real thing the page says, and yes, we're keeping it.)

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🌸 APPLICATION USAGE 🌸

None. that's it. she said nothing. 💅

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🦋 RATIONALE 🦋

None. also nothing. the silence is deafening but honestly? slay. ✨

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⭐ FUTURE DIRECTIONS ⭐

None. no plans, no notes, no future. just vibes. 🧚

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🍓 SEE ALSO 🍓

• The System Interfaces volume of POSIX.1‐2017, assert() — go read that one if you want the actual behavior deets, iykyk. 👀

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💜 COPYRIGHT 💜

okay legal bestie, listen up, we gotta do this part properly:

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!! 🎉💖 we did it. big thanks to IEEE/The Open Group, 2017, who brought you assert.h(0P) — that's the version and the date, right there at the bottom, where the footer lives. mwah. 😘 go assert something. 👑✨