1OPENSSL_config(3) OpenSSL OPENSSL_config(3)
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6 OPENSSL_config, OPENSSL_no_config - simple OpenSSL configuration
7 functions
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10 #include <openssl/conf.h>
11 void OPENSSL_config(const char *config_name);
13 void OPENSSL_no_config(void);
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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.
21 OPENSSL_no_config() disables configuration. If called before
23 OPENSSL_config() no configuration takes place.
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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.
32 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.
37 The environment variable OPENSSL_CONF can be set to specify the
39 location of the configuration file.
40 Currently ASN1 OBJECTs and ENGINE configuration can be performed future
42 versions of OpenSSL will add new configuration options.
43 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.
55 Applications should free up configuration at application closedown by
57 calling CONF_modules_free().
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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.
64 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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70 Neither OPENSSL_config() nor OPENSSL_no_config() return a value.
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73 conf(5), CONF_load_modules_file(3),
74 CONF_modules_free(3),CONF_modules_free(3)
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77 OPENSSL_config() and OPENSSL_no_config() first appeared in OpenSSL
78 0.9.7
791.0.1e 2013-02-11 OPENSSL_config(3)