The goal of this change is mainly to clean up Taisei's codebase and
improve its console output. I've been frustrated by files littered with
inconsistent printf/fprintf/warnx/errx calls for a long time, and now I
actually did something about it.
All the above functions are now considered deprecated and result in a
compile-time warning when used. Instead, the following macros should be
used:
log_debug(format, ...)
log_info(format, ...)
log_warn(format, ...)
log_err(format, ...)
As you can see, all of them have the same printf-like interface. But
they have different functionality and purpose:
log_debug is intended for very verbose and specific information. It
does nothing in release builds, much like assert(), so don't use
expressions with side-effects in its arguments.
log_info is for various status updates that are expected during
normal operation of the program.
log_warn is for non-critical failures or other things that may be
worth investigating, but don't inherently render the program
non-functional.
log_err is for when the only choice is to give up. Like errx, it
also terminates the program. Unlike errx, it actually calls abort(),
which means the cleanup functions are not ran -- but on the other
hand, you get a debuggable backtrace. However, if you're trying to
catch programming errors, consider using assert() instead.
All of them produce output that contains a timestamp, the log level
identifier, the calling function's name, and the formatted message.
The newline at the end of the format string is not required -- no, it is
actually *prohibited*. The logging system will take care of the line
breaks by itself, don't litter the code with that shit.
Internally, the logging system is based on the SDL_RWops abstraction,
and may have multiple, configurable destinations. This makes it easily
extensible. Currently, log_debug and log_info are set to write to
stdout, log_warn and log_err to stderr, and all of them also to the file
log.txt in the Taisei config directory.
Consequently, the nasty freopen hacks we used to make Taisei write to
log files on Windows are no longer needed -- which is a very good thing,
considering they probably would break if the configdir path contains
UTF-8 characters. SDL_RWFromFile does not suffer this limitation.
As an added bonus, it's also thread-safe.
Note about printf and fprintf: in very few cases, the logging system is
not a good substitute for these functions. That is, when you care about
writing exactly to stdout/stderr and about exactly how the output looks.
However, I insist on keeping the deprecation warnings on them to not
tempt anyone to use them for logging/debugging out of habit and/or
laziness.
For this reason, I've added a tsfprintf function to util.c. It is
functionally identical to fprintf, except it returns void. Yes, the name
is deliberately ugly. Avoid using it if possible, but if you must, only
use it to write to stdout or stderr. Do not write to actual files with
it, use SDL_RWops.
