bionic (3) mongoc_logging.3.gz

NAME

       mongoc_logging - Logging

       MongoDB C driver Logging Abstraction

SYNOPSIS

          typedef enum {
             MONGOC_LOG_LEVEL_ERROR,
             MONGOC_LOG_LEVEL_CRITICAL,
             MONGOC_LOG_LEVEL_WARNING,
             MONGOC_LOG_LEVEL_MESSAGE,
             MONGOC_LOG_LEVEL_INFO,
             MONGOC_LOG_LEVEL_DEBUG,
             MONGOC_LOG_LEVEL_TRACE,
          } mongoc_log_level_t;

          #define MONGOC_ERROR(...)
          #define MONGOC_CRITICAL(...)
          #define MONGOC_WARNING(...)
          #define MONGOC_MESSAGE(...)
          #define MONGOC_INFO(...)
          #define MONGOC_DEBUG(...)

          typedef void (*mongoc_log_func_t) (mongoc_log_level_t log_level,
                                             const char *log_domain,
                                             const char *message,
                                             void *user_data);

          void
          mongoc_log_set_handler (mongoc_log_func_t log_func, void *user_data);
          void
          mongoc_log (mongoc_log_level_t log_level,
                      const char *log_domain,
                      const char *format,
                      ...) BSON_GNUC_PRINTF (3, 4);
          const char *
          mongoc_log_level_str (mongoc_log_level_t log_level);
          void
          mongoc_log_default_handler (mongoc_log_level_t log_level,
                                      const char *log_domain,
                                      const char *message,
                                      void *user_data);
          void
          mongoc_log_trace_enable (void);
          void
          mongoc_log_trace_disable (void);

       The  MongoDB  C  driver  comes  with  an abstraction for logging that you can use in your application, or
       integrate with an existing logging system.

MACROS

       To make logging a little less painful, various helper macros are provided. See the following example.

          #undef MONGOC_LOG_DOMAIN
          #define MONGOC_LOG_DOMAIN "my-custom-domain"

          MONGOC_WARNING ("An error occurred: %s", strerror (errno));

CUSTOM LOG HANDLERS

       The default log handler prints a timestamp and the log message to stdout,  or  to  stderr  for  warnings,
       critical messages, and errors.
              You  can override the handler with mongoc_log_set_handler().  Your handler function is called in a
              mutex for thread safety.

       For example, you could register a custom handler to suppress messages at INFO level and below:

          void
          my_logger (mongoc_log_level_t log_level,
                     const char *log_domain,
                     const char *message,
                     void *user_data)
          {
             /* smaller values are more important */
             if (log_level < MONGOC_LOG_LEVEL_INFO) {
                mongoc_log_default_handler (log_level, log_domain, message, user_data);
             }
          }

          int
          main (int argc, char *argv[])
          {
             mongoc_init ();
             mongoc_log_set_handler (my_logger, NULL);

             /* ... your code ...  */

             mongoc_cleanup ();
             return 0;
          }

       To restore the default handler:

          mongoc_log_set_handler (mongoc_log_default_handler, NULL);

DISABLE LOGGING

       To disable all logging, including warnings, critical messages and errors, provide an empty log handler:

          mongoc_log_set_handler (NULL, NULL);

TRACING

       If compiling your own copy of the MongoDB C driver, consider configuring with --enable-tracing to  enable
       function tracing and hex dumps of network packets to STDERR and STDOUT during development and debugging.

       This is especially useful when debugging what may be going on internally in the driver.

       Trace    messages    can   be   enabled   and   disabled   by   calling   mongoc_log_trace_enable()   and
       mongoc_log_trace_disable()

       NOTE:
          Compiling the driver with  --enable-tracing  will  affect  its  performance.  Disabling  tracing  with
          mongoc_log_trace_disable() significantly reduces the overhead, but cannot remove it completely.

AUTHOR

       MongoDB, Inc

COPYRIGHT

       2018, MongoDB, Inc