wmempcpy(3)

🌸 wmempcpy(3) — wide-character memory return-offset-pointer copy 🌸

okay bestie sit DOWN because we're talking about wmempcpy and she is lowkey iconic for exactly one reason: she doesn't just copy ur wide characters, she tells u where she stopped. that's the whole personality. 💅

Library: Standard C library (libc, -lc) — yeah she's in libc, she's official, she's got papers. 🎀

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✨ SYNOPSIS ✨

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#include <wchar.h>

wchar_t *wmempcpy(size_t n;
              wchar_t dest[restrict n], const wchar_t src[restrict n],
              size_t n);

🚨 bestie listen: u need that #define _GNU_SOURCE before the #include <wchar.h> or she literally will not show up. (peep feature_test_macros(7) for the whole lore on why feature macros are like that.)

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💖 DESCRIPTION 💖

so. wmempcpy() is the wide-character equivalent of mempcpy(3). that's it, that's her whole deal — she's mempcpy but for wchar_t instead of plain bytes. 🦋

and the way to think about it? she's equivalent to this:

wmemcpy(dest, src, n) + n

like, literally. she does the copy, then she hands u back the pointer that's been scooted forward past everything she wrote. no cap. so instead of getting the start of the destination back, u get the end, which means u can just keep appending without doing any pointer math yourself. main character behavior fr fr. 👑

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🌈 RETURN VALUE 🌈

go check mempcpy(3) for the deets bestie, it's the same energy. ✨

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🫶 ATTRIBUTES 🫶

for the whole explanation of what these words even mean, attributes(7) has u covered. 📖

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

so basically she is MT-Safe — multiple threads can vibe with her at the same time and nobody's gonna catch a stray. slay. 💚

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👑 STANDARDS 👑

GNU. (yes she's a GNU girlie, she's built different, ur portable code might not have her 😭)

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🎀 HISTORY 🎀

she's been here since glibc 2.1. an OG. a legend. respect the elders. 🧚

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🔥 SEE ALSO 🔥

• mempcpy(3) — her byte-sized sibling, go say hi

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and that's the whole page bestie, u ate it, u understood it, we love to see it. 💜

this lil love letter came from Linux man-pages 6.20, dated 2026-08-10 — periodt. 🌸✨