freebsd man page for explicit_bzero

BZERO(3)						   BSD Library Functions Manual 						  BZERO(3)

NAME
     bzero, explicit_bzero -- write zeroes to a byte string

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <strings.h>

     void
     bzero(void *b, size_t len);

     void
     explicit_bzero(void *b, size_t len);

DESCRIPTION
     The bzero() function writes len zero bytes to the string b.  If len is zero, bzero() does nothing.

     The explicit_bzero() variant behaves the same, but will not be removed by a compiler's dead store optimization pass, making it useful for
     clearing sensitive memory such as a password.

SEE ALSO
     memset(3), swab(3)

HISTORY
     A bzero() function appeared in 4.3BSD.  Its prototype existed previously in <string.h> before it was moved to <strings.h> for IEEE Std
     1003.1-2001 (``POSIX.1'') compliance.

     The explicit_bzero() function first appeared in OpenBSD 5.5 and FreeBSD 11.0.

BSD
								  October 6, 2014							       BSD