TTYNAME(3P)

💖 hey bestie, welcome to TTYNAME(3P) 💖

okay so this is a page from the POSIX Programmer's Manual, and before we get into the fun stuff there's a lil heads-up.

🫶 PROLOG 🫶

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

fr fr, always double check your own platform's page before you ship anything, bestie 💅

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✨ NAME ✨

ttyname, ttyname_r — find the pathname of a terminal

like… "which terminal am I even on rn" but make it a syscall 🎀

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🌸 SYNOPSIS 🌸

#include <unistd.h>

char *ttyname(int fildes);
int ttyname_r(int fildes, char *name, size_t namesize);

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🦋 DESCRIPTION 🦋

So ttyname() shall return a pointer to a string containing a null-terminated pathname of the terminal associated with file descriptor fildes. Do NOT modify the string it hands you — the application shall not modify the string returned. The returned pointer might be invalidated, or the string content might be overwritten, by a subsequent call to ttyname(). The returned pointer and the string content might also be invalidated if the calling thread is terminated. 😭

The ttyname() function need not be thread-safe. it's giving chaotic single-thread energy, no cap

The ttyname_r() function shall store the null-terminated pathname of the terminal associated with the file descriptor fildes in the character array referenced by name. The array is namesize characters long and should have space for the name and the terminating null character. The maximum length of the terminal name shall be {TTY_NAME_MAX}. 👑

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💅 RETURN VALUE 💅

Upon successful completion, ttyname() shall return a pointer to a string. Otherwise, a null pointer shall be returned and errno set to indicate the error.

If successful, the ttyname_r() function shall return zero. Otherwise, an error number shall be returned to indicate the error.

so like… 0 = slay, nonzero = not slay, and for ttyname() a null pointer is the "it's not giving" signal 🌈

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🎀 ERRORS 🎀

The ttyname() function may fail if:

• EBADF — The fildes argument is not a valid file descriptor. (bestie that's not a real fd 💀)
• ENOTTY — The file associated with the fildes argument is not a terminal. (you handed me a file, not a tty, and I simply cannot 🙈)

The ttyname_r() function may fail if:

• EBADF — The fildes argument is not a valid file descriptor.
• ENOTTY — The file associated with the fildes argument is not a terminal.
• ERANGE — The value of namesize is smaller than the length of the string to be returned including the terminating null character. (your buffer is too smol, bestie, the name literally will not fit 😭)

The following sections are informative.

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🍓 EXAMPLES 🍓

None.

not a single example. iconic of them honestly 🫶

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⭐ APPLICATION USAGE ⭐

None.

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🧚 RATIONALE 🧚

The term terminal'' is used instead of the historical term terminal device'' in order to avoid a reference to an undefined term.

The thread-safe version places the terminal name in a user-supplied buffer and returns a non-zero value if it fails. The non-thread-safe version may return the name in a static data area that may be overwritten by each call.

tl;dr: ttyname_r = you bring your own buffer, it tells you if it messed up. ttyname = it hands you a pointer to a static area that the next call can just… overwrite. main character energy but make it fragile 🎀

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🌈 FUTURE DIRECTIONS 🌈

None.

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🔥 SEE ALSO 🔥

• The Base Definitions volume of POSIX.1‐2017, <unistd.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 to you from IEEE/The Open Group, dated 2017, and it lives in the POSIX Programmer's Manual under TTYNAME(3P). stay hydrated, close your file descriptors, and go find your terminal 🦋✨