memmove(3)

💖 memmove(3) — memory move 💖

okay bestie, we're doing a libc classic today. this is memmove, from the Library Functions Manual (that's the man page section, she's a 3 🫶), and yes she's that girl.

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✨ NAME ✨

memmove — memory move

lowkey the most self-explanatory name in the whole libc and honestly? iconic for that.

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📚 LIBRARY 📚

Standard C library (libc, -lc)

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🎀 SYNOPSIS 🎀

#include <string.h>  // see memory.h(3head)

void *memmove(size_t n;
              void dest[n], const void src[n], size_t n);

so you're gonna need #include <string.h> (and psst, check memory.h(3head) too, she's mentioned there as well). then you call her with n, dest[n], src[n] and n — yes the n shows up twice in that signature, that's not a typo, that's just how the page says it. 💅

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🌸 DESCRIPTION 🌸

This function is similar to memcpy(3), but the memory areas may overlap.

that's the whole tea. that's the entire description. memcpy(3) is the sister but she CANNOT handle overlapping regions — if your dest and src are vibing in the same neighbourhood, memcpy(3) fumbles it. memmove says "not on my watch" and handles the overlap just fine. no cap. 💖

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🦋 RETURN VALUE 🦋

See memcpy(3).

(translation for the girlies who don't wanna tab-flip: the return value deets live over on that page, this one is just pointing. go check her 🫶)

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👑 ATTRIBUTES 👑

For an explanation of the terms used in this section, see attributes(7).

• Interface: memmove()
  • Attribute: Thread safety
  • Value: MT-Safe 💅

MT-Safe means she's safe to call from multiple threads at once, go off queen.

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⭐ STANDARDS ⭐

C11, POSIX.1-2008.

certified, standardised, validated. periodt.

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🌈 HISTORY 🌈

POSIX.1-2001, C89, SVr4, 4.3BSD.

she's been around since forever, a true elder icon, main character energy since C89.

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💜 SEE ALSO 💜

• memory.h(3head)
• memcpy(3)
• wmemmove(3)

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and that's the whole page bestie, you ate that 🍓✨

source: Linux man-pages 6.20, dated 2026-08-10 — mwah, thanks for coming to my ted talk 🎀💖