PTSNAME(3P)

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

💖 PTSNAME(3P) — the POSIX bestie guide 💖

okay so real talk, this one lives in the POSIX Programmer's Manual (that's the manual name, bestie, it's literally right there in the title) and it's giving "short but important." ✨

🌸 PROLOG 🌸

so like, heads up before we even start: this page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ (so go check the corresponding Linux manual page for the tea on Linux behavior), or the interface might not even be implemented on Linux at all. no cap. 💀

👑 NAME 👑

ptsname — get name of the slave pseudo-terminal device. that's the whole job. she's focused. 💅

✨ SYNOPSIS ✨

#include <stdlib.h>

char *ptsname(int fildes);

🦋 DESCRIPTION 🦋

okay so here's the vibe. the ptsname() function shall return the name of the slave pseudo-terminal device associated with a master pseudo-terminal device. like, you got the master, she's got a slave, and ptsname() is the friend who tells you the slave's name. 🫶

the fildes argument is a file descriptor that refers to the master device.

and then ptsname() shall return a pointer to a string containing the pathname of the corresponding slave device. that's it, that's the whole function, iconic behavior honestly. ⭐

⚠️ real talk: the ptsname() function need not be thread-safe. so like, don't be out here assuming she can handle multiple threads at once. she said "one at a time bestie." 😭

💜 RETURN VALUE 💜

upon successful completion, ptsname() shall return a pointer to a string which is the name of the pseudo-terminal slave device. slay. ✨

upon failure, ptsname() shall return a null pointer and may set errno. when does this happen? well:

  • if fildes is an invalid file descriptor, or
  • if the slave device name does not exist in the file system. 😬

and now the important part, the part where you gotta listen:

🚨 the application shall not modify the string returned. do not touch. hands off. 🙈

the returned pointer might be invalidated, or the string content might be overwritten, by a subsequent call to ptsname(). and the returned pointer and the string content might also be invalidated if the calling thread is terminated. so like... don't be holding onto that pointer like it's your forever girl. it's not. it's temporary. main character energy but make it ephemeral. 💀

🔥 ERRORS 🔥

the ptsname() function may fail if:

  • EBADF — the fildes argument is not a valid file descriptor. bestie that's not a real fd, that's a vibe. 😭
  • ENOTTY — the file associated with the fildes argument is not a master pseudo-terminal device. wrong device, wrong era, wrong everything. 💅

and then the page says, and I quote the energy: the following sections are informative. 📢

🌈 EXAMPLES 🌈

None. there are no examples. she said "figure it out, you got this." ✨

🎀 APPLICATION USAGE 🎀

None. nothing to add. the page is simply not doing that today. 💖

🧚 RATIONALE 🧚

See the RATIONALE section for posix_openpt(). that's where the lore lives, go read that one. 📚

⭐ FUTURE DIRECTIONS ⭐

None. the future is... unchanged. she's staying exactly as she is. 👑

💫 SEE ALSO 💫

go check these out, they're all in the same friend group:

  • grantpt()
  • open()
  • posix_openpt()
  • ttyname()
  • unlockpt()

and also the Base Definitions volume of POSIX.1‐2017, specifically <stdlib.h>. 🌸

okay legal moment, gotta be precise here, no paraphrasing the lawyers:

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!! 💖 this one's from IEEE/The Open Group, 2017, and it's PTSNAME(3P) — go forth and get that slave pseudo-terminal name, you absolute legend. 🦋✨🎀

📦 where this page comes from