Re: Logging Library-GSOC

[Werner LEMBERG]

> When I am redirecting stderr logs to a text file using: `main
> arial.ttf qwertyuiopasdfghjklzxcvbnm 2>sdterr_logs.txt` I am getting
> the following results:
>
> `FT_LOGGING`: 8 sec
> `FT_DEBUG_LEVEL_TRACE`: 11 sec

This still looks fishy.

>> Otherwise I guess the big difference between `FT_LOGGING` and
>> `FT_DEBUG_LEVEL_TRACE` is due to file buffering.  In other words,
>> data sent to `stderr` gets output line by line to the screen, which
>> is slow, while data sent to the log file gets buffered completely,
>> and it is written to the disk in asynchronously to avoid write
>> delays.
> 
> I guess this is only the reason for the difference between the time
> values of `FT_LOGGING` and `FT_DEBUG_LEVEL_TRACE`...

Probably yes.  At least the difference between the two approaches
shouldn't be *that* large, I believe.

>> Maybe it makes sense to use C function `setvbuf` to exactly control
>> the buffering mode of the output file descriptor.
> 
> Ok, I will try this one out, but I guess using the `setvbuf()` in no
> buffering mode for writing logs to a file will give the same time
> value as time value produced when logs are written to stderr line by
> line...

Well, for comparison purposes the buffering mode should be the same
for `FT_LOGGING` and `FT_DEBUG_LEVEL_TRACE`.


    Werner