GETUID(3P)

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

okay so we're in the POSIX Programmer's Manual rn, that's the whole vibe of this page. no cap.

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🫶 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.

translation: this is the POSIX spec version of the tea, not necessarily what your specific Linux box does. check the Linux page if you want the Linux-specific lore, and also maybe it's just... not on Linux at all. 🙈

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✨ NAME ✨

getuid — get a real user ID 👑

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🌸 SYNOPSIS 🌸

#include <unistd.h>

uid_t getuid(void);

that's it. no args, no drama, she takes nothing and gives you everything. main character energy fr. 💅

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🦋 DESCRIPTION 🦋

The getuid() function shall return the real user ID of the calling process. The getuid() function shall not modify errno.

not touching errno?? iconic behaviour. she minds her own business. we love a function that doesn't leave a mess. ✨

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🎀 RETURN VALUE 🎀

The getuid() function shall always be successful and no return value is reserved to indicate the error.

like... she literally cannot fail. she's that girl. 💖

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💀 ERRORS 💀

No errors are defined.

The following sections are informative.

zero errors. none. empty list. the error section is giving "nothing to see here" and honestly? slay.

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🌈 EXAMPLES 🌈

🧚 Setting the Effective User ID to the Real User ID

The following example sets the effective user ID of the calling process to the real user ID.

#include <unistd.h>
...
seteuid(getuid());

so you grab your real uid with getuid() and yeet it straight into seteuid(). bestie combo. 🫶

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💜 APPLICATION USAGE 💜

None.

literally nothing. the application usage section said "no thoughts, head empty". 🎈

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⭐ RATIONALE ⭐

In a conforming environment, getuid() will always succeed. It is possible for implementations to provide an extension where a process in a non-conforming environment will not be associated with a user or group ID. It is recommended that such implementations return (uid_t)-1 and set errno to indicate such an environment; doing so does not violate this standard, since such an environment is already an extension.

okay so real talk: in a normal conforming world she always wins. but if someone's out here in a non-conforming environment with no user or group ID at all, the recommended move is to return (uid_t)-1 and set errno. and that's not a violation of the standard, because that environment is already an extension anyway. iykyk. 😭

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🔥 FUTURE DIRECTIONS 🔥

None.

she's not going anywhere. no plans, no changes, just vibes. periodt. 💅

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👑 SEE ALSO 👑

• getegid()
• geteuid()
• getgid()
• setegid()
• seteuid()
• setgid()
• setregid()
• setreuid()
• setuid()

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

the whole uid/gid friend group 💖 go read their pages too, they're all connected, it's giving found family.

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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!! brought to you by IEEE/The Open Group, 2017, page GETUID(3P) — stay hydrated, read your man pages, and remember: getuid() never fails you. mwah 💖✨