+YAZ_BEGIN_CDECL
+
+/** \brief log level: fatal */
+#define YLOG_FATAL 0x00000001
+/** \brief log level: debugging */
+#define YLOG_DEBUG 0x00000002
+/** \brief log level: warning */
+#define YLOG_WARN 0x00000004
+/** \brief log level: log (regular) */
+#define YLOG_LOG 0x00000008
+/** \brief log level: append system error message */
+#define YLOG_ERRNO 0x00000010
+/** \brief log level: append thread Id */
+#define YLOG_TID 0x00000020
+/** \brief log level: application */
+#define YLOG_APP 0x00000040
+/** \brief log level: malloc debug */
+#define YLOG_MALLOC 0x00000080
+/** \brief log level: do not output date and time */
+#define YLOG_NOTIME 0x00000100
+/** \brief log level: application 2 */
+#define YLOG_APP2 0x00000200
+/** \brief log level: application 3 */
+#define YLOG_APP3 0x00000400
+/** \brief log level: flush */
+#define YLOG_FLUSH 0x00000800
+/** \brief dynamic log level start */
+#define YLOG_LOGLVL 0x00001000 /* log when modules query log levels */
+ /* this has to be a hard-coded bit, not to loop*/
+
+#define YLOG_ALL (0xffff&~YLOG_MALLOC&~YLOG_NOTIME)
+
+/** \brief default log level */
+#define YLOG_DEFAULT_LEVEL \
+ (YLOG_FATAL | YLOG_ERRNO | YLOG_LOG | YLOG_WARN | YLOG_FLUSH)
+/* not having flush here confuses Solaris users, who won't see any logs until
+ * (and if) the program exits normally */
+
+/** \brief last bit for regular log bits . Rest are dynamic */
+#define YLOG_LAST_BIT YLOG_LOGLVL
+
+/** \brief sets level, prefix and filename for logging
+ \param level log level
+ \param prefix log message prefix
+ \param fname filename
+
+ If fname is NULL, the filename logging is not changed.
+*/
+YAZ_EXPORT void yaz_log_init(int level, const char *prefix, const char *fname);
+
+/** \brief sets log file
+ \param fname filename
+
+ A filename of NULL makes the log to be completely disabled.
+ A filename which is the empty string ("") makes the system
+ log to stderr (which is also the default). Otherwise the
+ filename given is used.
+*/
+YAZ_EXPORT void yaz_log_init_file(const char *fname);
+
+/** \brief sets log level
+ \param level (combination of YLOG_..)
+*/
+YAZ_EXPORT void yaz_log_init_level(int level);
+
+/** \brief sets log message prefix
+ \param prefix log message prefix
+*/
+YAZ_EXPORT void yaz_log_init_prefix(const char *prefix);
+
+/** \brief sets second log message prefix
+ \param prefix log message prefix
+*/
+YAZ_EXPORT void yaz_log_init_prefix2(const char *prefix);
+
+/** \brief sets time format for log mesages
+ \param fmt format (strftime)
+
+ Sets the format of the timestamp. See man 3 strftime.
+ Calling with "old" sets to the old format "11:55:06-02/11"
+ Calling with NULL or "" sets to the new format "20041102-115719"
+ If not called at all, the old format is used, for backward compatibility
+*/
+YAZ_EXPORT void yaz_log_time_format(const char *fmt);
+
+/** \brief sets limit in bytes for size for log file
+ \param mx size in bytes
+
+ Sets the max size for a log file. Zero means no limit.
+ Negative means built-in limit (1GB)
+*/
+YAZ_EXPORT void yaz_log_init_max_size(int mx);
+
+/** \brief Writes log message
+ \param level log level mask
+ \param fmt format string ala printf
+
+ Writes an entry in the log. Defaults to stderr if not initialized or
+ to a file with yaz_log_init_file(). The level must match the level set
+ via yaz_log_init_level(), optionally defined via yaz_log_mask_str().
+*/
+YAZ_EXPORT void yaz_log(int level, const char *fmt, ...)
+#ifdef __GNUC__
+ __attribute__ ((format (printf, 2, 3)))