> For example: the index format uses %-15.15L
> And I found out that these 15.15 is working like the C printf.
> So I tried to find some info which explains what C printf is.
> The only thing I found was some complicated mathematics about this
> being a format of telling how a printer is going to bring that to
> paper when digging somewhere in the groff pages. But this may not be
> related.
Have you tried man printf(3)? ;-)
[...]
- A negative field width flag `-' indicates the converted value is
to be left adjusted on the field boundary. Except for n conver-
sions, the converted value is padded on the right with blanks,
rather than on the left with blanks or zeros. A `-' overrides a
`0' if both are given.
[...]
o An optional decimal digit string specifying a minimum field width.
If the converted value has fewer characters than the field width, it
will be padded with spaces on the left (or right, if the left-adjust-
ment flag has been given) to fill out the field width.
o An optional precision, in the form of a period `.' followed by an op-
tional digit string. If the digit string is omitted, the precision
is taken as zero. This gives the minimum number of digits to appear
for d, i, o, u, x, and X conversions, the number of digits to appear
after the decimal-point for e, E, and f conversions, the maximum num-
ber of significant digits for g and G conversions, or the maximum
number of characters to be printed from a string for s conversions.
