STRNCAT(3POSIX)

💅 STRNCAT — the <string.h> girlies' guide

ok so bestie, we're reading STRNCAT(3POSIX), straight out of the POSIX Programmer's Manual, no cap. Sit down, grab a strawberry 🍓, and let's get into it.

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✨ PROLOG ✨

real talk before we even start: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so like, go check the corresponding Linux manual page for the deets on Linux behavior), or honestly the interface may not be implemented on Linux at all. 🙈 iykyk.

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👑 NAME 👑

strncat — concatenate a string with part of another

like... glue a little piece of one string onto the end of another. iconic behavior honestly. 🦋

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🌸 SYNOPSIS 🌸

#include <string.h>

char *strncat(char *restrict s1, const char *restrict s2, size_t n);

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💖 DESCRIPTION 💖

ok so first things first: 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 — and this volume of POSIX.1‐2017 defers to the ISO C standard. so if they ever beef, C wins. periodt.

now the actual tea ☕ — strncat() shall append not more than n bytes (a NUL character and bytes that follow it are not appended) from the array pointed to by s2 to the end of the string pointed to by s1.

the initial byte of s2 overwrites the NUL character at the end of s1. the way it just... bulldozes that terminator. 😭

a terminating NUL character is always appended to the result. always. every time. no exceptions. 🎀

⚠️ but babes, listen: if copying takes place between objects that overlap, the behavior is undefined. undefined. not "a little weird", not "mostly fine" — undefined. do not do it. that's the scary one. 💀

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🌈 RETURN VALUE 🌈

strncat() shall return s1 — and no return value shall be reserved to indicate an error. so like, the return value is never gonna rat out a problem for you. it just hands you s1 and vibes. 🫶

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⭐ ERRORS ⭐

No errors are defined. zero. none. the error list is empty, the vibes are immaculate.

The following sections are informative. (translation: the rest of this page is context, not requirements — cute but not binding 💅)

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🧚 EXAMPLES 🧚

None. nope. nothing here. moving on bestie 🦋

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🎀 APPLICATION USAGE 🎀

None. also empty. we're just breezing through at this point. ✨

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💜 RATIONALE 💜

None. the reasoning section said "no thoughts, head empty" and honestly? respect. 🙈

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🔥 FUTURE DIRECTIONS 🔥

None. the future is unspecified and that's lowkey freeing. 🌈

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🌟 SEE ALSO 🌟

• strcat()

and also — the Base Definitions volume of POSIX.1‐2017, specifically <string.h>. go say hi. 👋

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💅 COPYRIGHT 💅

ok legal bestie moment, this part is important so we're doing it 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!! 🥳 you now know strncat() better than like 90% of people who use it. go forth and concatenate responsibly — and remember, overlapping objects = undefined behavior, so don't be messy. 💖

IEEE/The Open Group — 2017 — STRNCAT(3POSIX) — mwah, kiss kiss, see you in the next man page. 🎀✨🦋💅