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# C Date and time utilities

From cppreference.com
< cpp‎ | chrono

### [edit] Functions

Defined in header `<ctime>`
##### Time manipulation
difftime | computes the difference between times (function) [edit]
time | returns the current time of the system as time since epoch (function) [edit]
clock | returns raw processor clock time since the program is started (function) [edit]
timespec_get (since C++17) | returns the calendar time based on a given time base (function) [edit]
##### Format conversions
asctime | converts a `tm` object to a textual representation (function) [edit]
ctime | converts a `time_t` object to a textual representation (function) [edit]
strftime | converts a `tm` object to custom textual representation (function) [edit]
wcsftime | converts a tm object to custom wide string textual representation (function) [edit]
gmtime | converts time since epoch to calendar time expressed as Universal Coordinated Time (function) [edit]
localtime | converts time since epoch to calendar time expressed as local time (function) [edit]
mktime | converts calendar time to time since epoch (function) [edit]

### [edit] Constants

CLOCKS_PER_SEC | number of processor clock ticks per second (macro constant) [edit]

### [edit] Types

tm | calendar time type (class) [edit]
time_t | time since epoch type (typedef) [edit]
clock_t | process running time (typedef) [edit]
timespec (since C++17) | time in seconds and nanoseconds (struct) [edit]

### [edit] See also

C documentation for Date and time utilities

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