[444] | 1 | @node Timefns |
---|
| 2 | @chapter Time Functions (@file{time.h}) |
---|
| 3 | |
---|
| 4 | This chapter groups functions used either for reporting on time |
---|
| 5 | (elapsed, current, or compute time) or to perform calculations based |
---|
| 6 | on time. |
---|
| 7 | |
---|
| 8 | The header file @file{time.h} defines three types. @code{clock_t} and |
---|
| 9 | @code{time_t} are both used for representations of time particularly |
---|
| 10 | suitable for arithmetic. (In this implementation, quantities of type |
---|
| 11 | @code{clock_t} have the highest resolution possible on your machine, |
---|
| 12 | and quantities of type @code{time_t} resolve to seconds.) @code{size_t} |
---|
| 13 | is also defined if necessary for quantities representing sizes. |
---|
| 14 | |
---|
| 15 | @file{time.h} also defines the structure @code{tm} for the traditional |
---|
| 16 | representation of Gregorian calendar time as a series of numbers, with |
---|
| 17 | the following fields: |
---|
| 18 | |
---|
| 19 | @table @code |
---|
| 20 | @item tm_sec |
---|
| 21 | Seconds, between 0 and 60 inclusive (60 allows for leap seconds). |
---|
| 22 | |
---|
| 23 | @item tm_min |
---|
| 24 | Minutes, between 0 and 59 inclusive. |
---|
| 25 | |
---|
| 26 | @item tm_hour |
---|
| 27 | Hours, between 0 and 23 inclusive. |
---|
| 28 | |
---|
| 29 | @item tm_mday |
---|
| 30 | Day of the month, between 1 and 31 inclusive. |
---|
| 31 | |
---|
| 32 | @item tm_mon |
---|
| 33 | Month, between 0 (January) and 11 (December). |
---|
| 34 | |
---|
| 35 | @item tm_year |
---|
| 36 | Year (since 1900), can be negative for earlier years. |
---|
| 37 | |
---|
| 38 | @item tm_wday |
---|
| 39 | Day of week, between 0 (Sunday) and 6 (Saturday). |
---|
| 40 | |
---|
| 41 | @item tm_yday |
---|
| 42 | Number of days elapsed since last January 1, between 0 and 365 inclusive. |
---|
| 43 | |
---|
| 44 | @item tm_isdst |
---|
| 45 | Daylight Savings Time flag: positive means DST in effect, zero means DST |
---|
| 46 | not in effect, negative means no information about DST is available. |
---|
| 47 | Although for mktime(), negative means that it should decide if DST is in |
---|
| 48 | effect or not. |
---|
| 49 | @end table |
---|
| 50 | |
---|
| 51 | @menu |
---|
| 52 | * asctime:: Format time as string |
---|
| 53 | * clock:: Cumulative processor time |
---|
| 54 | * ctime:: Convert time to local and format as string |
---|
| 55 | * difftime:: Subtract two times |
---|
| 56 | * gmtime:: Convert time to UTC (GMT) traditional representation |
---|
| 57 | * localtime:: Convert time to local representation |
---|
| 58 | * mktime:: Convert time to arithmetic representation |
---|
| 59 | * strftime:: Convert date and time to a user-formatted string |
---|
| 60 | * time:: Get current calendar time (as single number) |
---|
| 61 | * __tz_lock:: Lock time zone global variables |
---|
| 62 | * tzset:: Set timezone info |
---|
| 63 | @end menu |
---|
| 64 | |
---|
| 65 | @page |
---|
| 66 | @include time/asctime.def |
---|
| 67 | |
---|
| 68 | @page |
---|
| 69 | @include time/clock.def |
---|
| 70 | |
---|
| 71 | @page |
---|
| 72 | @include time/ctime.def |
---|
| 73 | |
---|
| 74 | @page |
---|
| 75 | @include time/difftime.def |
---|
| 76 | |
---|
| 77 | @page |
---|
| 78 | @include time/gmtime.def |
---|
| 79 | |
---|
| 80 | @page |
---|
| 81 | @include time/lcltime.def |
---|
| 82 | |
---|
| 83 | @page |
---|
| 84 | @include time/mktime.def |
---|
| 85 | |
---|
| 86 | @page |
---|
| 87 | @include time/strftime.def |
---|
| 88 | |
---|
| 89 | @page |
---|
| 90 | @include time/time.def |
---|
| 91 | |
---|
| 92 | @page |
---|
| 93 | @include time/tzlock.def |
---|
| 94 | |
---|
| 95 | @page |
---|
| 96 | @include time/tzset.def |
---|