GRANTPT(3P)

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

🎀 PROLOG 🎀

okay bestie, real talk before we dive in 💖 this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so like, go check the corresponding Linux manual page for the tea on Linux behavior, fr), or honestly the interface may not be implemented on Linux at all. 🙈

✨ NAME ✨

grantpt — grant access to the slave pseudo-terminal device 🫶

🌸 SYNOPSIS 🌸

#include <stdlib.h>

int grantpt(int fildes);

💅 DESCRIPTION 💅

So here's the vibe: the grantpt() function shall change the mode and ownership of the slave pseudo-terminal device that's associated with its master pseudo-terminal counterpart. Iconic, I know. 👑

The fildes argument is a file descriptor that refers to a master pseudo-terminal device.

The user ID of the slave shall be set to the real UID of the calling process, and the group ID shall be set to an unspecified group ID (yeah, it's giving mysterious, don't ask 🦋).

The permission mode of the slave pseudo-terminal shall be set to:

  • readable and writable by the owner
  • writable by the group
⚠️ okay but listen — the behavior of the grantpt() function is unspecified if the application has installed a signal handler to catch SIGCHLD signals. Not "undefined", not "bad", just unspecified, which is its own whole thing. Be aware. 💀

🔥 RETURN VALUE 🔥

  • Upon successful completion, grantpt() shall return 0 — slay. ✨
  • Otherwise, it shall return -1 and set errno to indicate the error. 😭

💜 ERRORS 💜

The grantpt() function may fail if:

  • EACCES — The corresponding slave pseudo-terminal device could not be accessed. 🚫
  • EBADF — The fildes argument is not a valid open file descriptor. 🙅
  • EINVAL — The fildes argument is not associated with a master pseudo-terminal device. 💀

The following sections are informative. (translation: cute but not the law, iykyk 🧚)

🌈 EXAMPLES 🌈

None.

(not me giving you nothing but honesty 💅)

🍓 APPLICATION USAGE 🍓

None.

⭐ RATIONALE ⭐

See the RATIONALE section for posix_openpt(). That's it, that's the whole thing, go read the other one bestie 🫶

🦋 FUTURE DIRECTIONS 🦋

None.

👑 SEE ALSO 👑

  • open()
  • posix_openpt()
  • ptsname()
  • unlockpt()

Also, the Base Definitions volume of POSIX.1‐2017, <stdlib.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!! 💖 this little cutie came to you from the POSIX Programmer's Manual, courtesy of IEEE/The Open Group, dated 2017 — stay hydrated, read your standards, and remember: grantpt said "i got you" and meant it. 🎀✨🦋

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