1OPENSSL_config(3)                   OpenSSL                  OPENSSL_config(3)
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NAME

6       OPENSSL_config, OPENSSL_no_config - simple OpenSSL configuration
7       functions
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SYNOPSIS

10        #include <openssl/conf.h>
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12        void OPENSSL_config(const char *config_name);
13        void OPENSSL_no_config(void);
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DESCRIPTION

16       OPENSSL_config() configures OpenSSL using the standard openssl.cnf
17       configuration file name using config_name. If config_name is NULL then
18       the default name openssl_conf will be used. Any errors are ignored.
19       Further calls to OPENSSL_config() will have no effect. The
20       configuration file format is documented in the conf(5) manual page.
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22       OPENSSL_no_config() disables configuration. If called before
23       OPENSSL_config() no configuration takes place.
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NOTES

26       It is strongly recommended that all new applications call
27       OPENSSL_config() or the more sophisticated functions such as
28       CONF_modules_load() during initialization (that is before starting any
29       threads). By doing this an application does not need to keep track of
30       all configuration options and some new functionality can be supported
31       automatically.
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33       It is also possible to automatically call OPENSSL_config() when an
34       application calls OPENSSL_add_all_algorithms() by compiling an
35       application with the preprocessor symbol OPENSSL_LOAD_CONF #define'd.
36       In this way configuration can be added without source changes.
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38       The environment variable OPENSSL_CONF can be set to specify the
39       location of the configuration file.
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41       Currently ASN1 OBJECTs and ENGINE configuration can be performed future
42       versions of OpenSSL will add new configuration options.
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44       There are several reasons why calling the OpenSSL configuration
45       routines is advisable. For example new ENGINE functionality was added
46       to OpenSSL 0.9.7.  In OpenSSL 0.9.7 control functions can be supported
47       by ENGINEs, this can be used (among other things) to load dynamic
48       ENGINEs from shared libraries (DSOs).  However very few applications
49       currently support the control interface and so very few can load and
50       use dynamic ENGINEs. Equally in future more sophisticated ENGINEs will
51       require certain control operations to customize them. If an application
52       calls OPENSSL_config() it doesn't need to know or care about ENGINE
53       control operations because they can be performed by editing a
54       configuration file.
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56       Applications should free up configuration at application closedown by
57       calling CONF_modules_free().
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RESTRICTIONS

60       The OPENSSL_config() function is designed to be a very simple "call it
61       and forget it" function. As a result its behaviour is somewhat limited.
62       It ignores all errors silently and it can only load from the standard
63       configuration file location for example.
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65       It is however much better than nothing. Applications which need finer
66       control over their configuration functionality should use the
67       configuration functions such as CONF_load_modules() directly.
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RETURN VALUES

70       Neither OPENSSL_config() nor OPENSSL_no_config() return a value.
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SEE ALSO

73       conf(5), CONF_load_modules_file(3),
74       CONF_modules_free(3),CONF_modules_free(3)
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HISTORY

77       OPENSSL_config() and OPENSSL_no_config() first appeared in OpenSSL
78       0.9.7
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821.0.0e                            2005-06-02                 OPENSSL_config(3)
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