ISBLANK(3POSIX)

💖 ISBLANK — test for a blank character 💖

okay bestie, welcome to the POSIX Programmer's Manual ✨ this one's about isblank and isblank_l, and yes it's short, and yes it still ate. iykyk.

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🌸 PROLOG 🌸

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

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✨ NAME ✨

isblank, isblank_l — test for a blank character 🎀

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🦋 SYNOPSIS 🦋

#include <ctype.h>

int isblank(int c);
int isblank_l(int c, locale_t locale);

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💜 DESCRIPTION 💜

okay so, for isblank() specifically: 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, no cap.

The isblank() and isblank_l() functions shall test whether c is a character of class blank in the current locale, or in the locale represented by locale, respectively. (if you wanna know what "blank" even means, go see the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale 👀)

The c argument is a type int, and the value of it — the application shall ensure it's a character representable as an unsigned char, or equal to the value of the macro EOF. > if the argument has any other value, the behavior is undefined 😭 so pls don't.

also, the behavior is undefined if the locale argument to isblank_l() is the special locale object LC_GLOBAL_LOCALE, or if it's not a valid locale object handle. not me warning you twice 💀

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👑 RETURN VALUE 👑

isblank() and isblank_l() shall return non-zero if c is a <blank>; otherwise, they shall return 0. periodt.

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🌈 ERRORS 🌈

No errors are defined. iconic behavior honestly, nothing to worry about 🫶

The following sections are informative.

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🍓 EXAMPLES 🍓

None. (yes, literally none. we're keeping it real. nothing to show bestie 🙈)

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🧚 APPLICATION USAGE 🧚

To ensure applications portability — especially across natural languages — only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification. don't go rogue, ok? 🌸

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⭐ RATIONALE ⭐

None.

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💫 FUTURE DIRECTIONS 💫

None.

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🔥 SEE ALSO 🔥

• isalnum()
• isalpha()
• iscntrl()
• isdigit()
• isgraph()
• islower()
• isprint()
• ispunct()
• isspace()
• isupper()
• isxdigit()
• setlocale()
• uselocale()

and also the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, plus <ctype.h> and <locale.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!! 🌈✨ this one came from IEEE/The Open Group, 2017 — thanks for reading, mwah 💅🫶💖