is a convenience function to get the prefix of the preferred hash method. If a preferred method is available, it is the same as the one also used by the

if their given

parameter is NULL.

The string returned equals the prefix of the preferred hash method. If no preferred hash method is available it is NULL. It

safe to pass the string returned by

directly to

without prior string-sanitizing nor NULL-pointer checks.

will define the macro

if

is available in the current version of libxcrypt.

The function

is not part of any standard. It was added to libxcrypt in version 4.4.0.

For an explanation of the terms used in this section, see