STRSPN(3P)

📦 version 2017a, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, nixpkgs unstable, opensuse-leap 16.0

💖 STRSPN(3P) — the POSIX Programmer's Manual, bestie edition 💖

okay so before we even get into it — this page lives in the POSIX Programmer's Manual, and that's a whole thing. let me set the scene.

🌸 PROLOG 🌸

so like, this manual page is part of the POSIX Programmer's Manual. the tea is: 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 just not be implemented on Linux at all. it's giving "results may vary" 💅

✨ NAME ✨

strspn — get length of a substring. that's it, that's the whole vibe. she's short, she's sweet, she measures things. 👑

🎀 SYNOPSIS 🎀

#include <string.h>

size_t strspn(const char *s1, const char *s2);

look at her. two const char * girlies and a size_t return. iconic. no cap. 🦋

💅 DESCRIPTION 💅

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? unintentional, fr. this volume of POSIX.1‐2017 defers to the ISO C standard. so if they ever beef, ISO C wins. periodt.

okay now the actual function, and honestly it's kind of elegant:

the strspn() function shall compute the length (in bytes) of the maximum initial segment of the string pointed to by s1 which consists entirely of bytes from the string pointed to by s2. 🫶

like. she walks along s1 from the very start, byte by byte, and keeps going as long as every byte she meets is one of the bytes chilling inside s2. the second she hits a byte that is NOT in s2, she stops and tells you how far she got. that's the whole plot. main character energy honestly. ✨

⭐ RETURN VALUE ⭐

the strspn() function shall return the computed length. and here's the cute part — no return value is reserved to indicate an error. she simply cannot fail. she just counts. no error girlies allowed. 😭💖

💀 ERRORS 💀

no errors are defined.

and then — the following sections are informative. (iykyk, informative means "not the binding rules, just vibes and context" 🧚)

🙈 EXAMPLES 🙈

none.

🌈 APPLICATION USAGE 🌈

none.

💜 RATIONALE 💜

none.

🔥 FUTURE DIRECTIONS 🔥

none.

🦋 SEE ALSO 🦋

  • strcspn()
  • the Base Definitions volume of POSIX.1‐2017, <string.h>

okay bestie, legal moment, stay with me, this matters:

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 .

lowkey important: don't come for me about typos, they're probably from the file conversion, not from me. 🫶

and that's the page!! this one came to you from IEEE/The Open Group, 2017, and the page itself is STRSPN(3P). go measure some substrings, bestie, you're gonna slay. 💖✨🎀

📦 where this page comes from