Currently, the only working function is io_libc:fwrite/2, io_libc:format/2 is alias for it.
To format strings faster, call io_libc:format instead of io_lib:format, providing C-style fmt string.
Example:
> io_libc:format("hello, %08.3f, %s %04X!", [3.14, dead, 48879]).
<<"hello, 0003.140, dead BEEF!">>
Numbers are converted automatically when needed, falling back to zero on error:
> io_libc:format("float %.1f, int %d, bad %d and %f", [3, 2.7, {eee}]).
<<"float 3.0, int 2, bad 0 and 0.000000">>
You can pass atom or any valid iolist as string value:
> io_libc:format("string %s, atom %s, bad '%s' and '%s'", [["abc", [<<"de">>], $f], hello, {foo}]).
<<"string abcdef, atom hello, bad '' and ''">>
Extra convertion arguments are also supported:
> io_libc:format("%*.*f; %0*d", [8, 3, 2.7, 6, 12]).
<<" 2.700; 000012">>