strndup(3)

✨ strndup — the manual, but make it cute ✨

okay bestie, buckle up, we're learning strndup(3) from the Library Functions Manual and honestly? it's giving underrated icon 💅

---

🌸 NAME 🌸

strndup — nonstring duplicate-into-string</p> 🎀

---

📚 LIBRARY 📚

the Standard C library (libc, link it with -lc) 🫶

---

🦋 SYNOPSIS 🦋

like this, no cap:

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

char *strndup(size_t n;
              const char strn[n], size_t n);

Feature Test Macro Requirements for glibc (peep feature_test_macros(7) for the tea ☕):

strndup():

• Since glibc 2.10: _POSIX_C_SOURCE >= 200809L
• Before glibc 2.10: _GNU_SOURCE

---

💖 DESCRIPTION 💖

okay so here's the vibe: this function duplicates at most n nonnull characters from the array that strn is pointing at, and then it tacks a null character on the end 🌱 — the whole thing lands in brand new memory that it got from malloc(3). new memory, who dis 💅

---

🌈 RETURN VALUE 🌈

on success, strndup() hands you back a pointer to the duplicated string ✨ it's slaying, it's iconic, it's your string now.

but if there wasn't enough memory available? it returns NULL 😭 and sets errno to show you what went wrong. rude, but okay.

---

💀 ERRORS 💀

just go look at malloc(3), bestie. it's all there 🫶

---

👑 ATTRIBUTES 👑

for the full explanation of the terms used in this section, see attributes(7) 🔍

here's the rundown:

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

so yeah — MT-Safe, meaning it's chill to call from multiple threads 💚

---

⭐ STANDARDS ⭐

POSIX.1-2008. periodt 🎀

---

🕰️ HISTORY 🕰️

also POSIX.1-2008. — yeah she's been around a minute, main character energy since day one 👑

---

🔥 SEE ALSO 🔥

• memory.h(3head)
• malloc(3)
• strndupa(3)

---

and that's the whole page, bestie!! this was Linux man-pages 6.20, dated 2026-08-17, and we were reading all about strndup(3) 🦋✨ go forth and duplicate responsibly, iykyk 💖