MEMCMP(3)              FreeBSD Library Functions Manual              MEMCMP(3)

NAME

     memcmp - compare bytes in memory

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <string.h>

     int
     memcmp(const void *b1, const void *b2, size_t len);

DESCRIPTION

     The memcmp() function compares byte object b1 against byte object b2.
     Both objects are assumed to be len bytes long.

RETURN VALUES

     The memcmp() function returns zero if the two objects are identical.
     Zero-length objects are considered identical.  The memcmp() function
     returns a negative value if the first differing byte has a lower value in
     b1 and a positive value if the first differing byte has a higher value in
     b1.

SEE ALSO

     bcmp(3), strcasecmp(3), strcmp(3), strcoll(3), strxfrm(3),
     timingsafe_memcmp(3), wmemcmp(3)

STANDARDS

     The memcmp() function conforms to ISO/IEC 9899:1990 ("ISO C90").

CAVEATS

     If the objects differ, the C library memcmp() implementation returns the
     difference between the first two differing bytes (treated as unsigned
     char values).  This behavior is not specified by ISO/IEC 9899:1990
     ("ISO C90"), is not portable, and may not occur in light of compiler
     optimizations.

FreeBSD 15.1-STABLE-HBSD       November 20, 2024                     MEMCMP(3)