ISGRAPH(3P)

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

okay so real talk: this page lives in the POSIX Programmer's Manual, and the very first thing you need to know is the prologue tea.

🫶 PROLOG

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ — so if you're on Linux, pls consult the corresponding Linux manual page for the deets on Linux behavior. Or, plot twist, the interface may not even be implemented on Linux. Vibe check before you ship, fr fr.

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✨ NAME ✨

isgraph, isgraph_l — test for a visible character 👀

Like, is this character giving visible? That's the whole job.

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🌸 SYNOPSIS 🌸

#include <ctype.h>

int isgraph(int c);
int isgraph_l(int c, locale_t locale);

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💅 DESCRIPTION 💅

for isgraph():

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 — no cap, nobody's trying to fight the ISO C standard. This volume of POSIX.1‐2017 defers to the ISO C standard. Periodt.

the actual function tea ☕

The isgraph() and isgraph_l() functions shall test whether c is a character of class graph in the current locale, or in the locale represented by locale, respectively. See the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale. (Yes bestie, locales are a whole thing. Chapter 7. Go read it. 🦋)

The c argument is an int, the value of which the application shall ensure is 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. Like, we don't know what happens. Nobody knows. Don't do it. 💀

🚨 The behavior is also undefined if the locale argument to isgraph_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. Do not pass a fake locale, bestie, it will not slay.

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👑 RETURN VALUE 👑

The isgraph() and isgraph_l() functions shall return non-zero if c is a character with a visible representation; otherwise, they shall return 0.

That's it. Non-zero = visible. Zero = not visible. Iconic and simple. 💖

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🎀 ERRORS 🎀

No errors are defined. ✨

The following sections are informative.

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🌈 EXAMPLES 🌈

None. 😭 (I know. The audacity. But it's true.)

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🦋 APPLICATION USAGE 🦋

To ensure applications portability — especially across natural languages, which is a whole mood — 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 with some random custom classifier, iykyk.

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💜 RATIONALE 💜

None. (Nothing to justify, she's just built different.)

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⭐ FUTURE DIRECTIONS ⭐

None. The future is, apparently, exactly the same as the present. Slay.

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🔥 SEE ALSO 🔥

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

Also, from the Base Definitions volume of POSIX.1‐2017:

• Chapter 7, Locale
• <ctype.h>
• <locale.h>

The whole character-classification squad, together at last. 🫶

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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 page, bestie!! this one came to you from IEEE/The Open Group, 2017, filed under ISGRAPH(3P) — go forth and classify your characters responsibly 💅✨