printf_buffered(), buffering for putchar_

[kjsdf7wr3]

printf from <stdio.h> provides buffering via some other internal functions.
It would be nice, if this repo offered a printf variant, which operates on a user provided buffer to reduce the calls to putchar_.

Example:

void puts_(const char * data, int length)
{
    // handle data block wise, instead of char wise like in putchar_
}

char buffer[10];
printf_buffered(buffer, sizeof(buffer), "0123456789+2");  // <-- calls puts_(buffer, 10); puts(buffer+10, 2);
printf_buffered(buffer, sizeof(buffer), "abc");          // <-- calls puts_(buffer, 3); 

Of course, one could also implement this kind of buffering inside putchar_, but at least if built without LTO, the performance would be quite a bit better for the printf_buffered.

[eyalroz]

This library's scope will not expand to also cover stream buffering. While it is certainly useful to have - if you want this...

• You can achieve this using fctprintf() - simply use a function which applies such buffering.
• Write a library depending on libprintf, which utilizes either fctprintf(), or sprintf_() into its buffer, to implement printf_buffered().