ISATTY(3P)

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

💖 ISATTY(3P) — the POSIX Programmer's Manual, but make it cute 💖

okay bestie, welcome to ISATTY(3P), straight out of the POSIX Programmer's Manual. pull up a chair, grab a boba, we're doing this 💅

🌸 PROLOG 🌸

bestie, real talk before we start: this page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ — so if you're on Linux, go check the corresponding Linux manual page for the deets. or, plot twist, the interface might not even be implemented on Linux at all. 🙈

✨ NAME ✨

isatty — the girl whose whole job is testing for a terminal device 🎀

🦋 SYNOPSIS 🦋

#include <unistd.h>

int isatty(int fildes);

💜 DESCRIPTION 💜

so isatty() shall test whether fildes — an open file descriptor, bestie, key detail — is associated with a terminal device. that's it. that's the function. she's simple, she's iconic, she knows her lane 👑

🔥 RETURN VALUE 🔥

  • returns 1 if fildes is associated with a terminal 🌈
  • otherwise returns 0, and may set errno to indicate the error

💀 ERRORS 💀

isatty() may fail if:

  • EBADF — the fildes argument is not a valid open file descriptor. like, girl, that fd isn't even real 😭
  • ENOTTY — the file associated with the fildes argument is not a terminal. it's a file, bestie. it's giving "just a file" 💅
also the following sections are informative — so they're the vibes-and-context part, not the legally-binding part. noted 📝

🌟 EXAMPLES 🌟

None. (literally none. the void. nothing to see here 🫶)

👑 APPLICATION USAGE 👑

okay this one matters, so listen up: isatty() does not necessarily indicate that a human being is available for interaction via fildes. it is quite possible that non-terminal devices are connected to the communications line. so like… a terminal doesn't mean a person, and a person doesn't mean a terminal. don't assume, bestie 😭

🧚 RATIONALE 🧚

None. (nope. nothing. moving on 💜)

🌈 FUTURE DIRECTIONS 🌈

None. (the future is a mystery, but this field is empty ✨)

🎀 SEE ALSO 🎀

  • The Base Definitions volume of POSIX.1‐2017, <unistd.h>

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 .

and that's the whole page, bestie!! 💖 shoutout to IEEE/The Open Group, 2017, for bringing us ISATTY(3P) — she ate, no cap. mwah, bye 🫶✨

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