ds_log.h

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#ifndef _DS_LOG_H_
#define _DS_LOG_H_
 
/* uses varargs */
#include <stdarg.h>
 
#include <odytypes.h>
 
/*
 * ds_log.h: public interface to the logging data structure
 */
 
/*
 * An abstract log:
 *     A log consists of the following abstract entities:
 *           A level of detail, "log_level"
 *           A stream to which output should be sent
 *           A level of detail above which each statement should be
 *              immediately flushed.
 *           A (potentially empty) text name
 *
 * A log's current level of detail describes how "verbose" the logs
 * should be.  Each logging statement should have a detail associated
 * with it; only statements whose level of detail are less than or
 * equal to the log's level are printed.  Others are (quickly) ignored.
 * If a log's level is above the flush level, each statement is followed
 * by an explicit flush on the stream.
 *
 * Each logging statement is stamped with the time of day, and day changes
 * are noted in the log.  Each logging statement is also stamped
 * with the log's name, to allow multiple logs to (unambiguously) share
 * the same stream.  These routines are not thread safe.
 */
 
typedef struct ds_log_t ds_log_t; /* logs are opaque */
 
/*** Observers ***/
 
extern bool ds_log_valid(ds_log_t *lp);
 
/*** Mutators ***/
 
extern ds_log_t *ds_log_create(int loglevel, FILE *fp, int flushlevel,
                               char *name);
 
extern FILE *ds_log_destroy(ds_log_t *lp);
 
extern void ds_log_setlevel(ds_log_t *lp, int level);
 
/*
 * printmsg appends a newline: you don't need one.
 * It's not a good idea to call this directly.  Use DS_LOG_MSG
 * instead;
 */
 
extern void ds_log_printmsg(ds_log_t *lp, int level, char *fmt, ...);
 
/* Use the macro, DS_LOG_MSG to do logging: this will allow you to turn
   off logging in performance-sensitive spots. */
 
#define DS_LOG_MSG(args) ds_log_printmsg args
 
#endif /* _DS_LOG_H_ */