Manual Pages for UNIX Operating System command usage for man OPENSSL_config

OpenSSL                                  OPENSSL_config(3openssl)



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     OPENSSL_config, OPENSSL_no_config - simple OpenSSL
     configuration functions

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      #include 

      void OPENSSL_config(const char *config_name);
      void OPENSSL_no_config(void);


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     OPENSSL_config() configures OpenSSL using the standard
     ooooppppeeeennnnssssssssllll....ccccnnnnffff configuration file name using ccccoooonnnnffffiiiigggg_nnnnaaaammmmeeee. If
     ccccoooonnnnffffiiiigggg_nnnnaaaammmmeeee is NULL then the default name ooooppppeeeennnnssssssssllll_ccccoooonnnnffff will
     be used. Any errors are ignored. Further calls to
     OPENSSL_config() will have no effect. The configuration file
     format is documented in the conf(5) manual page.

     OPENSSL_no_config() disables configuration. If called before
     OPENSSL_config() no configuration takes place.

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     It is ssssttttrrrroooonnnnggggllllyyyy recommended that aaaallllllll new applications call
     OPENSSL_config() or the more sophisticated functions such as
     CONF_modules_load() during initialization (that is before
     starting any threads). By doing this an application does not
     need to keep track of all configuration options and some new
     functionality can be supported automatically.

     It is also possible to automatically call OPENSSL_config()
     when an application calls OPENSSL_add_all_algorithms() by
     compiling an application with the preprocessor symbol
     OOOOPPPPEEEENNNNSSSSSSSSLLLL_LLLLOOOOAAAADDDD_CCCCOOOONNNNFFFF #define'd. In this way configuration can
     be added without source changes.

     The environment variable OOOOPPPPEEEENNNNSSSSSSSSLLLL_CCCCOOOONNNNFFFF can be set to specify
     the location of the configuration file.

     Currently ASN1 OBJECTs and ENGINE configuration can be
     performed future versions of OpenSSL will add new
     configuration options.

     There are several reasons why calling the OpenSSL
     configuration routines is advisable. For example new ENGINE
     functionality was added to OpenSSL 0.9.7.  In OpenSSL 0.9.7
     control functions can be supported by ENGINEs, this can be
     used (among other things) to load dynamic ENGINEs from
     shared libraries (DSOs).  However very few applications
     currently support the control interface and so very few can
     load and use dynamic ENGINEs. Equally in future more
     sophisticated ENGINEs will require certain control



2/Jun/2005             Last change: 0.9.8o                      1






OpenSSL                                  OPENSSL_config(3openssl)



     operations to customize them. If an application calls
     OPENSSL_config() it doesn't need to know or care about
     ENGINE control operations because they can be performed by
     editing a configuration file.

     Applications should free up configuration at application
     closedown by calling CONF_modules_free().

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     The OPENSSL_config() function is designed to be a very
     simple "call it and forget it" function. As a result its
     behaviour is somewhat limited. It ignores all errors
     silently and it can only load from the standard
     configuration file location for example.

     It is however mmmmuuuucccchhhh better than nothing. Applications which
     need finer control over their configuration functionality
     should use the configuration functions such as
     CONF_load_modules() directly.

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     Neither OPENSSL_config() nor OPENSSL_no_config() return a
     value.

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     conf(5), CONF_load_modules_file(3), the
     CONF_modules_free(3),CONF_modules_free(3) manpage

HHHHIIIISSSSTTTTOOOORRRRYYYY
     OPENSSL_config() and OPENSSL_no_config() first appeared in
     OpenSSL 0.9.7
























2/Jun/2005             Last change: 0.9.8o                      2