1COAP_LOGGING(3)                 libcoap Manual                 COAP_LOGGING(3)
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NAME

6       coap_logging, coap_log, coap_get_log_level, coap_set_log_level,
7       coap_set_log_handler, coap_package_name, coap_package_version,
8       coap_package_build, coap_set_show_pdu_output, coap_show_pdu,
9       coap_endpoint_str, coap_session_str - Work with CoAP logging
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SYNOPSIS

12       #include <coap3/coap.h>
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14       void coap_log(coap_log_t level, const char *format, ...);
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16       void coap_set_log_level(coap_log_t level);
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18       coap_log_t coap_get_log_level(void);
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20       void coap_dtls_set_log_level(int level);
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22       int coap_dtls_get_log_level(void);
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24       void coap_set_log_handler(coap_log_handler_t handler);
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26       const char *coap_package_name(void);
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28       const char *coap_package_version(void);
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30       const char *coap_package_build(void);
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32       void coap_set_show_pdu_output(int use_fprintf);
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34       void coap_show_pdu(coap_log_t level, const coap_pdu_t *pdu);
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36       const char *coap_endpoint_str(const coap_endpoint_t *endpoint);
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38       const char *coap_session_str(const coap_session_t *session);
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40       For specific (D)TLS library support, link with -lcoap-3-notls,
41       -lcoap-3-gnutls, -lcoap-3-openssl, -lcoap-3-mbedtls or
42       -lcoap-3-tinydtls. Otherwise, link with -lcoap-3 to get the default
43       (D)TLS library support.
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DESCRIPTION

46       The logging sub-system supports logging at different levels, and
47       depending on the selected logging level, outputs the appropriate
48       information.
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50       Logging by default is to stderr or stdout depending on the logging
51       level of the log entry. It ia possible to send the logging information
52       to an application logging callback handler for processing by the
53       application.
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55       The coap_log() function is used to log information at the appropriate
56       level. The rest of the parameters follow the standard printf() function
57       format.
58
59       Logging levels (coap_log_t) are defined by (the same as for syslog()),
60       which are numerically incrementing in value:
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62       LOG_EMERG
63           Emergency level (0).
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65       LOG_ALERT
66           Alert level (1).
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68       LOG_CRIT
69           Critical level (2).
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71       LOG_ERR
72           Error level (3).
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74       LOG_WARNING
75           Warning level (the default) (4).
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77       LOG_NOTICE
78           Notice level (5).
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80       LOG_INFO
81           Information level (6).
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83       LOG_DEBUG
84           Debug level (7).
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86       The coap_set_log_level() function is used to set the current logging
87       level for output by any subsequent coap_log() calls. Output is only
88       logged if the coap_log() level definition is smaller than or equal to
89       the current logging level.
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91       The coap_get_log_level() function is used to get the current logging
92       level.
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94       The coap_dtls_set_log_level() function is used to set the logging level
95       for output by the DTLS library for specific DTLS information. Usually,
96       both coap_set_log_level() and coap_dtls_set_log_level() would be set to
97       the same level value. If the logging level is set to greater than
98       LOG_DEBUG, the underlying TLS library may get more verbose in its
99       output.
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101       The coap_dtls_get_log_level() function is used to get the current
102       logging level for the DTLS library.
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104       The coap_set_log_handler()* function can be used to define an
105       alternative logging handler for processing the logging messages. The
106       logging handler prototype is defined as:
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108           typedef void (*coap_log_handler_t) (coap_log_t level, const char *message);
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110       The coap_package_name() function returns the name of this library.
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112       The coap_package_version() function returns the version of this
113       library.
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115       The coap_package_build() function returns the git information (as in
116       "git describe --tags") for the build of this library or version of this
117       library if git is not used.
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119       The coap_set_show_pdu_output() function defines whether the output from
120       coap_show_pdu() is to be either sent to stdout/stderr, or output using
121       coap_log(). use_fprintf is set to 1 for stdout/stderr (the default),
122       and use_fprintf is set to 0 for coap_log().
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124       The coap_show_pdu() function is used to decode the pdu, outputting as
125       appropriate for logging level. Where the output goes is dependent on
126       coap_set_show_pdu_output().
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128       The coap_endpoint_str() function returns a description string of the
129       endpoint.
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131       The coap_session_str() function is used to get a string containing the
132       information about the session.
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RETURN VALUES

135       The coap_package_name(), coap_package_version() and
136       coap_package_build() return the appropriate zero-terminated character
137       string.
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139       The coap_get_log_level() function returns the current logging level.
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141       The coap_dtls_get_log_level() function returns the current logging
142       level for the DTLS library specifics.
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144       The coap_endpoint_str() function returns a description string of the
145       endpoint.
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147       The coap_session_str() function returns a description string of the
148       session.
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SEE ALSO

151       coap_context(3) and coap_session(3)
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FURTHER INFORMATION

154       See "RFC7252: The Constrained Application Protocol (CoAP)" for further
155       information.
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BUGS

158       Please report bugs on the mailing list for libcoap:
159       libcoap-developers@lists.sourceforge.net or raise an issue on GitHub at
160       https://github.com/obgm/libcoap/issues
161

AUTHORS

163       The libcoap project <libcoap-developers@lists.sourceforge.net>
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167coap_logging 4.3.1                11/24/2022                   COAP_LOGGING(3)
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