man fmt_fill () - append spaces to a string
NAME
fmt_fill - append spaces to a string
SYNTAX
#include <fmt.h>
unsigned long fmt_fill(char *dest, unsigned long srclen, unsigned long padlen, unsigned long maxlen);
DESCRIPTION
fmt_fill appends padlen-srclen spaces (if that number is positive) to dest (which holds srclen bytes). It truncates the output only if the length would exceed maxlen.
It returns the number of bytes it wrote.
fmt_fill does not append \0.
If dest equals FMT_LEN (i.e. is zero), fmt_fill returns the number of bytes it would have written.