The trace bits are
1 Trace all function calls to lfuns.
2 Trace all calls to call_other
4 Trace all function returns.
8 Print argunents at function calls and return values.
16 Print all executed stack machine instructions (Avoid this flag, it produces massive output!).
32 Enable trace in heart beat functions (Avoid this flag, it constantly produces a lot of output!).
64 Trace calls to apply (Applies are driver internal call_others).
128 Show object name in tracing (Avoid this flag when you know what you are tracing!).
The master-lfun query_player_level() is called to verify the usage of this efun.
object obj;
string prefix;
obj=find_player("deepthought");
prefix=file_name(obj);
prefix=prefix[1..strlen(prefix)-1]; /* cut off the leading "/" */
traceprefix(prefix);
/* From here on, only code in the object "std/player#69"
* will be traced.
*/
trace(1|2|4|8);
...
trace(0);