| Constant | Category | Meaning | 
| CODESET | LC_CTYPE | Codeset name | 
| D_T_FMT | LC_TIME | String for formatting date and time | 
| D_FMT | LC_TIME | Date format string | 
| T_FMT | LC_TIME | Time format string | 
| T_FMT_AMPM | LC_TIME | A.M. or P.M. time format string | 
| AM_STR | LC_TIME | Ante-meridiem affix | 
| PM_STR | LC_TIME | Post-meridiem affix | 
| DAY_1 | LC_TIME | Name of the first day of the week (e.g.: Sunday) | 
| DAY_2 | LC_TIME | Name of the second day of the week (e.g.: Monday) | 
| DAY_3 | LC_TIME | Name of the third day of the week (e.g.: Tuesday) | 
| DAY_4 | LC_TIME | Name of the fourth day of the week (e.g.: Wednesday) | 
| DAY_5 | LC_TIME | Name of the fifth day of the week (e.g.: Thursday) | 
| DAY_6 | LC_TIME | Name of the sixth day of the week (e.g.: Friday) | 
| DAY_7 | LC_TIME | Name of the seventh day of the week (e.g.: Saturday) | 
| ABDAY_1 | LC_TIME | Abbreviated name of the first day of the week | 
| ABDAY_2 | LC_TIME | Abbreviated name of the second day of the week | 
| ABDAY_3 | LC_TIME | Abbreviated name of the third day of the week | 
| ABDAY_4 | LC_TIME | Abbreviated name of the fourth day of the week | 
| ABDAY_5 | LC_TIME | Abbreviated name of the fifth day of the week | 
| ABDAY_6 | LC_TIME | Abbreviated name of the sixth day of the week | 
| ABDAY_7 | LC_TIME | Abbreviated name of the seventh day of the week | 
| MON_1 | LC_TIME | Name of the first month of the year | 
| MON_2 | LC_TIME | Name of the second month | 
| MON_3 | LC_TIME | Name of the third month | 
| MON_4 | LC_TIME | Name of the fourth month | 
| MON_5 | LC_TIME | Name of the fifth month | 
| MON_6 | LC_TIME | Name of the sixth month | 
| MON_7 | LC_TIME | Name of the seventh month | 
| MON_8 | LC_TIME | Name of the eighth month | 
| MON_9 | LC_TIME | Name of the ninth month | 
| MON_10 | LC_TIME | Name of the tenth month | 
| MON_11 | LC_TIME | Name of the eleventh month | 
| MON_12 | LC_TIME | Name of the twelfth month | 
| ABMON_1 | LC_TIME | Abbreviated name of the first month | 
| ABMON_2 | LC_TIME | Abbreviated name of the second month | 
| ABMON_3 | LC_TIME | Abbreviated name of the third month | 
| ABMON_4 | LC_TIME | Abbreviated name of the fourth month | 
| ABMON_5 | LC_TIME | Abbreviated name of the fifth month | 
| ABMON_6 | LC_TIME | Abbreviated name of the sixth month | 
| ABMON_7 | LC_TIME | Abbreviated name of the seventh month | 
| ABMON_8 | LC_TIME | Abbreviated name of the eighth month | 
| ABMON_9 | LC_TIME | Abbreviated name of the ninth month | 
| ABMON_10 | LC_TIME | Abbreviated name of the tenth month | 
| ABMON_11 | LC_TIME | Abbreviated name of the eleventh month | 
| ABMON_12 | LC_TIME | Abbreviated name of the twelfth month | 
| ERA | LC_TIME | Era description segments | 
| ERA_D_FMT | LC_TIME | Era date format string | 
| ERA_D_T_FMT | LC_TIME | Era date and time format string | 
| ERA_T_FMT | LC_TIME | Era time format string | 
| ALT_DIGITS | LC_TIME | Alternative symbols for digits | 
| RADIXCHAR | LC_NUMERIC | Radix character | 
| THOUSEP | LC_NUMERIC | Separator for thousands | 
| YESEXPR | LC_MESSAGES | Affirmative response expression | 
| NOEXPR | LC_MESSAGES | Negative response expression |