ASSERT(3P)

💅 ASSERT(3P) — the POSIX Programmer's Manual era 💅

okay bestie, welcome to ASSERT(3P), straight outta the POSIX Programmer's Manual, no cap. this is the page you want when your program needs to ✨scream✨ the second something goes wrong.

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🫶 PROLOG 🫶

so, real talk: this manual page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ — like, consult the corresponding Linux manual page for the tea on Linux behavior — or honestly the interface may not even be implemented on Linux at all. 🙈

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🌸 NAME 🌸

assert — insert program diagnostics. she's little, she's dramatic, she's essential. 💖

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✨ SYNOPSIS ✨

#include <assert.h>

void assert(scalar expression);

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🦋 DESCRIPTION 🦋

bestie, the functionality described on this reference page is aligned with the ISO C standard. any conflict between the requirements described here and the ISO C standard is unintentional. this volume of POSIX.1‐2017 defers to the ISO C standard. periodt.

The assert() macro shall insert diagnostics into programs; it shall expand to a void expression. so when it runs, if expression (which shall have a scalar type) is false — that is, it compares equal to 0 — then assert() shall write info about the particular call that failed on stderr, and shall call abort(). it's giving "main character catches the bug and immediately ends the whole show." 💀

The info written about the call that failed shall include:

• the text of the argument
• the name of the source file
• the source file line number
• the name of the enclosing function

and those last three are, respectively, the values of the preprocessing macros __FILE__ and __LINE__ and of the identifier __func__. like she literally doxxes the exact spot in your code that lied to you. iconic. 👑

forcing a definition of the name NDEBUG, either from the compiler command line or with the preprocessor control statement #define NDEBUG ahead of the #include <assert.h> statement, shall stop assertions from being compiled into the program. so if you define NDEBUG, she's gone. poof. not in the binary. that's the vibe check for production builds. 🧚

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🌈 RETURN VALUE 🌈

the assert() macro shall not return a value. she does not do returns, bestie. she does consequences. 💅

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⭐ ERRORS ⭐

no errors are defined. none. zero. nothing to report. 🎀

The following sections are informative.

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🍓 EXAMPLES 🍓

None. (yes, literally none. we're all just out here rawdogging it. 😭)

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💜 APPLICATION USAGE 💜

None.

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🌟 RATIONALE 🌟

None.

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🔥 FUTURE DIRECTIONS 🔥

None.

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💖 SEE ALSO 💖

• abort()
• stdin

The Base Definitions volume of POSIX.1‐2017, <assert.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 🫶 courtesy of IEEE/The Open Group, dated 2017 — she's been serving diagnostics realness since way back, and honestly? still ate. 💅✨🌸