memory.h(3head)                                                memory.h(3head)

NAME
       memory.h - memory operations

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <memory.h>

DESCRIPTION
   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
       In some systems (Illumos), <memory.h> contains only a few of these
       functions, and thus <string.h> is needed.

STANDARDS
       BSD.

       These functions are also provided in <string.h>, as specified by ISO C.
       This is a historic mistake maintained for compatibility reasons; these
       functions aren't string APIs.

HISTORY
       SVr1, 4.3BSD.

       System V (1983) introduced an initial set of mem* functions in a
       <memory.h> header file.  4.3BSD (1986) adopted them.

       SVID Issue 1 (1985) standardized this header file, but stated that the
       functions would be moved to <string.h>.

       XPG Issue 3 (1989) listed <memory.h> as WITHDRAWN, and stated that the
       functions had been moved to <string.h>.

       C89 didn't standardize this header file and instead specified all these
       functions in <string.h>.

       This merge of header files has historically confused programmers about
       the real purpose of these functions.

       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>.

SEE ALSO
       string(3), string_copying(7)

Linux man-pages 6.19              2026-08-10                   memory.h(3head)