memory.h(3head)

💖 memory.h — NAME 💖

okay bestie so like, memory.h is literally the memory operations header 💅 that's it that's the vibe, no cap

---

📚 LIBRARY

Standard C library (libc, -lc) 🫶

---

✨ SYNOPSIS ✨

#include <memory.h>

---

🌸 DESCRIPTION 🌸

this header is giving "one stop shop for poking at memory" and honestly? iconic 👑

🖊️ Write

• bzero(3)
• explicit_bzero(3)
• memset(3)
• memset_explicit(3)

📋 Copy

• memmove(3)
• memcpy(3)
• mempcpy(3)
• memccpy(3)
• strncpy(3)
• stpncpy(3)

🧵 Catenate

• strncat(3)

👯 Duplicate

• strndup(3)
• strndupa(3)

⚖️ Compare

• memeq(3)
• memcmp(3)
• strncmp(3)
• strncasecmp(3)

🔍 Search

• memchr(3)
• memrchr(3)
• memmem(3)

---

🦋 VERSIONS

so on some systems (looking at you, Illumos 👀) <memory.h> only has a couple of these functions in it, which means you also need <string.h> to get the rest. annoying? yes. slay? no. 💀

---

👑 STANDARDS

BSD.

these functions also live in <string.h>, as specified by ISO C. and bestie let me tell you why — it's a historic mistake that everyone just kept around for compatibility reasons 🫠 these are not string APIs, fr fr, they never were.

the way the standard just leaked mem* stuff into a string header and now we all live like this 😭

---

🌈 HISTORY 🌈

SVr1, 4.3BSD.

okay so storytime 📖:

• System V (1983) introduced the initial set of mem* functions in a <memory.h> header file. so that's where it all started ✨
• 4.3BSD (1986) adopted them. slay, we stan adoption 🫶
• SVID Issue 1 (1985) standardized this header file, BUT said the functions were gonna get moved to <string.h>. foreshadowing much? 👀
• XPG Issue 3 (1989) listed <memory.h> as WITHDRAWN, and said the functions had been moved to <string.h>. periodt 💅
• C89 didn't standardize this header file at all, and instead specified all these functions in <string.h>.

this whole merge of header files has historically confused programmers about the real purpose of these functions. like genuinely, that's the legacy 😭

most C libraries — including the BSDs, glibc, musl, Bionic, and Illumos — continue to provide <memory.h>. 💖

gnulib doesn't provide it, though, and instead uses <string.h>. not gnulib doing its own thing 🙈

---

🔗 SEE ALSO

• string(3)
• string_copying(7)

---

and that's the whole page, bestie! this little love letter to memory.h(3head) was brought to you by Linux man-pages 6.20, dated 2026-08-10 — go forth and memset responsibly 🎀✨💜