# CRYPT_PREFERRED_METHOD - get the prefix of the preferred hash method - man(3) - [phpMan]

[_CRYPT_PREFERRED_METHOD_(3)](https://www.chedong.com/phpMan.php/man/CRYPTPREFERREDMETHOD/3/markdown)              Library Functions Manual            [_CRYPT_PREFERRED_METHOD_(3)](https://www.chedong.com/phpMan.php/man/CRYPTPREFERREDMETHOD/3/markdown)

## NAME
       crypt_preferred_method — get the prefix of the preferred hash method

## LIBRARY
       Crypt Library (libcrypt, -lcrypt)

## SYNOPSIS
### #include <crypt.h>

       _const_ _char*_
       **crypt_preferred_method**(_void_);

## DESCRIPTION
       **crypt_preferred_method  **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
       **crypt_gensalt functions**, if their given _prefix_ parameter is NULL.

## RETURN VALUES
       The  string  returned  equals  the prefix of the preferred hash method.  If no preferred hash
       method  is  available  it  is  NULL.   It  _is_  safe  to   pass   the   string   returned   by
       **crypt_preferred_method  **directly  to  **crypt_gensalt **without prior string-sanitizing nor NULL-
       pointer checks.

## FEATURE TEST MACROS
       <_crypt.h_> will define the macro CRYPT_PREFERRED_METHOD_AVAILABLE if **crypt_preferred_method **is
       available in the current version of libxcrypt.

## PORTABILITY NOTES
       The function **crypt_preferred_method **is not part of any standard.  It was added  to  libxcrypt
       in version 4.4.0.

## ATTRIBUTES
       For an explanation of the terms used in this section, see [_attributes_(7)](https://www.chedong.com/phpMan.php/man/attributes/7/markdown).
       ┌────────────────────────┬───────────────┬─────────┐
       │ **Interface              **│ **Attribute     **│ **Value   **│
       ├────────────────────────┼───────────────┼─────────┤
       │ **crypt_preferred_method **│ Thread safety │ MT-Safe │
       └────────────────────────┴───────────────┴─────────┘


## SEE ALSO
       [_crypt_gensalt_(3)](https://www.chedong.com/phpMan.php/man/cryptgensalt/3/markdown)

libxcrypt                                 November 16, 2018                [_CRYPT_PREFERRED_METHOD_(3)](https://www.chedong.com/phpMan.php/man/CRYPTPREFERREDMETHOD/3/markdown)