The GCC 5 compiler with -Wpedantic enabled generates warnings for the
non-standard predefined identifier __FUNCTION___. These warnings can be
avoided by using the C99 identifier __func__ instead.
The main logging function isn't really suitable for generating inline
hexdumps directly from the binary data. There is simply no format string
available for converting array data types with just a single printf
call.
A possible solution would be to require the caller to perform the string
conversion before calling the standard logging function. But that's not
acceptable, because it doesn't play well with the ability to disable the
logging at compile time, requires extra memory and clutters the calling
code unneccessary.
The new function is a compromise which sacrifices flexibility for
simplicity, by using a hardcoded output format with a custom prefix.
It's not a perfect solution, but it works well enough for the intended
purpose.
When the logging is disabling, several compiler warnings regarding
unused variables appear. With the cast to void and sizeof trick the
warnings are silenced without causing any side effects.
With the new option, the library can be compiled with the entire
logging infrastructure disabled. The public api remains unchanged, but
the internal logging functions will have no effect anymore.
In practice the overhead of the logging functions should be quite
small, and disabling the logging at runtime might be more convenient.
Especially because troubleshooting will become much harder without any
logging.
The new convenience function provides a centralized and threadsafe
function for logging system errors. The previous functions are
deprecated and will be removed after the transition to the new context
based logging.
With the introduction of a context object, library initialization and
shutdown can be performed without requiring any global state. A single
process can use multiple independent contexts without any problems. The
lack of a global state also improves the thread-safety of the library.
At the moment, the new context object is primary used to implement an
improved logging system.
