10.7 Handling Culture-Specific Information

Each locale contains the following cultural information:

• Date and time information

  The LC_TIME category defines the conventions for writing date and time, the names of the days of the week, and the names of months of the year.

• Numeric information

  The LC_NUMERIC category defines the conventions for formatting non-monetary values.

• Monetary information

  The LC_MONETARY category defines currency symbols and the conventions used to format monetary values.

• Yes and no responses

  The LC_MESSAGES category defines the strings expected in response to yes/no questions.

You can extract some of this cultural information using the nl_langinfo function and the localeconv function. See Section 10.7.1.

10.7.1 Extracting Cultural Information From a Locale

The nl_langinfo function returns a pointer to a string that contains an item of information obtained from the program's current locale. The information you can extract from the locale is:

• Date and time formats

• The names of the days of the week, and months of the year in the local language

• The radix character

• The character used to separate groups of digits in non- monetary values

• The currency symbol

• The name of the codeset for the locale

• The strings defined for responses to yes/no questions

The localeconv function returns a pointer to a data structure that contains numeric formatting and monetary formatting data from the LC_NUMERIC and LC_MONETARY categories.

10.7.2 Date and Time Formatting Functions

The functions that use the date and time information are:

• strftime-takes date and time values stored in a data structure and formats them into an output string. The format of the output string is controlled by a format string.

• strptime-converts a string (of type char) into date and time values. A format string defines how the string is interpreted.

• wcsftime-does the same as strftime except that it creates a wide-character string.

10.7.3 Monetary Formatting Function

The strfmon function uses the monetary information in a locale to convert a number of values into a string. The format of the string is controlled by a format string.

10.7.4 Numeric Formatting

The information in LC_NUMERIC is used by various functions. For example, strtod, wcstod, and the print and scan functions determine the radix character from the LC_NUMERIC category.