These are the standard members of struct lconv; there may be
others.

char *decimal_point

char *mon_decimal_point

These are the decimal-point separators used in formatting non-monetary
and monetary quantities, respectively. In the `C' locale, the
value of decimal_point is ".", and the value of
mon_decimal_point is "".

char *thousands_sep

char *mon_thousands_sep

These are the separators used to delimit groups of digits to the left of
the decimal point in formatting non-monetary and monetary quantities,
respectively. In the `C' locale, both members have a value of
"" (the empty string).

char *grouping

char *mon_grouping

These are strings that specify how to group the digits to the left of
the decimal point. grouping applies to non-monetary quantities
and mon_grouping applies to monetary quantities. Use either
thousands_sep or mon_thousands_sep to separate the digit
groups.
Each member of these strings is to be interpreted as an integer value of
type char. Successive numbers (from left to right) give the
sizes of successive groups (from right to left, starting at the decimal
point.) The last member is either 0, in which case the previous
member is used over and over again for all the remaining groups, or
CHAR_MAX, in which case there is no more grouping—or, put
another way, any remaining digits form one large group without
separators.

For example, if grouping is "\04\03\02", the correct
grouping for the number 123456787654321 is `12', `34',
`56', `78', `765', `4321'. This uses a group of 4
digits at the end, preceded by a group of 3 digits, preceded by groups
of 2 digits (as many as needed). With a separator of `,', the
number would be printed as `12,34,56,78,765,4321'.

A value of "\03" indicates repeated groups of three digits, as
normally used in the U.S.

In the standard `C' locale, both grouping and
mon_grouping have a value of "". This value specifies no
grouping at all.

char int_frac_digits

char frac_digits

These are small integers indicating how many fractional digits (to the
right of the decimal point) should be displayed in a monetary value in
international and local formats, respectively. (Most often, both
members have the same value.)

In the standard `C' locale, both of these members have the value
CHAR_MAX, meaning “unspecified”. The ISO standard doesn't say
what to do when you find this value; we recommend printing no
fractional digits. (This locale also specifies the empty string for
mon_decimal_point, so printing any fractional digits would be
confusing!)

Published under the terms of the GNU General Public License