The category argument allows a specific category of the locale settings to be used for fetching a message. Valid categories are:
LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, LC_MESSAGES and LC_ALL.
Note that the category must be specified with a numeric value, instead of the constant name. The values are:
LC_CTYPE 0
LC_NUMERIC 1
LC_TIME 2
LC_COLLATE 3
LC_MONETARY 4
LC_MESSAGES 5
LC_ALL 6
bindtextdomain