futimes(3)

✨ futimes(3) — change file timestamps ✨

okay bestie, welcome to the futimes page 💖 — that's futimes and its little sibling lutimes, two tiny glibc cuties that let you mess with a file's access and modification times. They live in the Standard C library, a.k.a. libc (link with -lc), so you already have them, no cap 🌸

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🌈 SYNOPSIS 🌈

#include <sys/time.h>

int futimes(int fd, const struct timeval tv[2]);
int lutimes(const char *path, const struct timeval tv[2]);

🎀 Feature Test Macro Requirements for glibc 🎀

(peep feature_test_macros(7) if you're confused, queen)

futimes(), lutimes():

• Since glibc 2.19:
  • _DEFAULT_SOURCE
• glibc 2.19 and earlier:
  • _BSD_SOURCE

fr fr, define the right macro before you include anything, or these functions will ghost you 🙈

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💅 DESCRIPTION 💅

futimes() changes the access and modification times of a file exactly the same way utimes(2) does — the only glow-up is that you tell it which file via a file descriptor, fd, instead of a pathname. it's giving "I already have the fd open, why would I re-open by path" energy 😌

lutimes() also changes access and modification times just like utimes(2), but with one iconic twist: if path points at a symbolic link, the link does not get dereferenced. instead, it changes the timestamps of the symbolic link itself 🦋 (yes, links have timestamps too, main character behavior honestly)

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⭐ RETURN VALUE ⭐

• On success: 0 is returned 🎉
• On error: -1 is returned, and errno is set to tell you what went wrong 😭

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🔥 ERRORS 🔥

Errors are as for utimes(2), plus these extra ones for futimes():

• EBADF — fd is not a valid file descriptor. bestie that fd is not real 💀
• ENOSYS — the /proc filesystem could not be accessed.

And this additional error can happen for lutimes():

• ENOSYS — the kernel does not support this call; Linux 2.6.22 or later is required. old kernel? no lutimes for you 🫶

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👑 ATTRIBUTES 👑

for the whole explanation of what these terms mean, go read attributes(7) — iykyk

• Interface: futimes(), lutimes()
  • Attribute: Thread safety
  • Value: MT-Safe

so yes, they're thread-safe. slay 🎀

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🌟 STANDARDS 🌟

Linux, BSD.

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🧚 HISTORY 🧚

• futimes() — glibc 2.3.
• lutimes() — glibc 2.6.

glow-up timeline, honestly 📈

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💜 NOTES 💜

lutimes() is implemented using the utimensat(2) system call. that's the whole tea ☕

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🌸 SEE ALSO 🌸

utime(2), utimensat(2), symlink(7)

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lowkey reminder: futimes() takes an fd, lutimes() takes a path and doesn't follow symlinks. don't mix them up bestie 😭

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and that's the page, periodt 💅 this was Linux man-pages 6.20, dated 2026-02-08 — mwah, go change some timestamps responsibly 🦋✨