zabrane/io_libc

io_libc -- fast formatter NIF for Erlang using standard C library

API

Currently, the only working function is io_libc:fwrite/2, io_libc:format/2 is alias for it.

Usage

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">>